Bump gatsby-source-filesystem from 2.1.15 to 2.1.18

Bumps [gatsby-source-filesystem](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-source-filesystem) from 2.1.15 to 2.1.18.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-source-filesystem/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-source-filesystem@2.1.18/packages/gatsby-source-filesystem)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

yarn.lock

@@ -3383,7 +3383,22 @@ cheerio@^1.0.0-rc.3:
     lodash "^4.15.0"
     parse5 "^3.0.1"
 
-chokidar@2.1.8, chokidar@^2.0.2, chokidar@^2.0.3, chokidar@^2.0.4, chokidar@^2.1.6:
+chokidar@3.0.2:
+  version "3.0.2"
+  resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-3.0.2.tgz#0d1cd6d04eb2df0327446188cd13736a3367d681"
+  integrity sha512-c4PR2egjNjI1um6bamCQ6bUNPDiyofNQruHvKgHQ4gDUP/ITSVSzNsiI5OWtHOsX323i5ha/kk4YmOZ1Ktg7KA==
+  dependencies:
+    anymatch "^3.0.1"
+    braces "^3.0.2"
+    glob-parent "^5.0.0"
+    is-binary-path "^2.1.0"
+    is-glob "^4.0.1"
+    normalize-path "^3.0.0"
+    readdirp "^3.1.1"
+  optionalDependencies:
+    fsevents "^2.0.6"
+
+chokidar@^2.0.2, chokidar@^2.0.3, chokidar@^2.0.4, chokidar@^2.1.6:
   version "2.1.8"
   resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-2.1.8.tgz#804b3a7b6a99358c3c5c61e71d8728f041cff917"
   integrity sha512-ZmZUazfOzf0Nve7duiCKD23PFSCs4JPoYyccjUFF3aQkQadqBhfzhjkwBH2mNOG9cTBwhamM37EIsIkZw3nRgg==
@@ -3402,21 +3417,6 @@ chokidar@2.1.8, chokidar@^2.0.2, chokidar@^2.0.3, chokidar@^2.0.4, chokidar@^2.1
   optionalDependencies:
     fsevents "^1.2.7"
 
-chokidar@3.0.2:
-  version "3.0.2"
-  resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-3.0.2.tgz#0d1cd6d04eb2df0327446188cd13736a3367d681"
-  integrity sha512-c4PR2egjNjI1um6bamCQ6bUNPDiyofNQruHvKgHQ4gDUP/ITSVSzNsiI5OWtHOsX323i5ha/kk4YmOZ1Ktg7KA==
-  dependencies:
-    anymatch "^3.0.1"
-    braces "^3.0.2"
-    glob-parent "^5.0.0"
-    is-binary-path "^2.1.0"
-    is-glob "^4.0.1"
-    normalize-path "^3.0.0"
-    readdirp "^3.1.1"
-  optionalDependencies:
-    fsevents "^2.0.6"
-
 chownr@^1.0.1, chownr@^1.1.1:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/chownr/-/chownr-1.1.2.tgz#a18f1e0b269c8a6a5d3c86eb298beb14c3dd7bf6"
@@ -5802,11 +5802,16 @@ file-type@5.2.0, file-type@^5.2.0:
   resolved "https://registry.yarnpkg.com/file-type/-/file-type-5.2.0.tgz#2ddbea7c73ffe36368dfae49dc338c058c2b8ad6"
   integrity sha1-LdvqfHP/42No365J3DOMBYwritY=
 
-file-type@^10.11.0, file-type@^10.7.0:
+file-type@^10.7.0:
   version "10.11.0"
   resolved "https://registry.yarnpkg.com/file-type/-/file-type-10.11.0.tgz#2961d09e4675b9fb9a3ee6b69e9cd23f43fd1890"
   integrity sha512-uzk64HRpUZyTGZtVuvrjP0FYxzQrBf4rojot6J65YMEbwBLB0CWm0CLojVpwpmFmxcE/lkvYICgfcGozbBq6rw==
 
+file-type@^12.2.0:
+  version "12.2.0"
+  resolved "https://registry.yarnpkg.com/file-type/-/file-type-12.2.0.tgz#bc4bce830e38a96a0ecfea0e2dfcee2855ed1380"
+  integrity sha512-bkDBeH5doAqP69axEO69OviLlWbrZ10Ne2OPHaxBgG+fyT0w/2zfMzJz21SPwq5Iq0aN70q7RN3KRcdUY427Mg==
+
 file-type@^3.8.0:
   version "3.9.0"
   resolved "https://registry.yarnpkg.com/file-type/-/file-type-3.9.0.tgz#257a078384d1db8087bc449d107d52a52672b9e9"
@@ -6062,15 +6067,6 @@ fs-extra@^4.0.3:
     jsonfile "^4.0.0"
     universalify "^0.1.0"
 
-fs-extra@^5.0.0:
-  version "5.0.0"
-  resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-5.0.0.tgz#414d0110cdd06705734d055652c5411260c31abd"
-  integrity sha512-66Pm4RYbjzdyeuqudYqhFiNBbCIuI9kgRqLPSHIlXHidW8NIQtVdkM1yeZ4lXwuhbTETv3EUGMNHAAw6hiundQ==
-  dependencies:
-    graceful-fs "^4.1.2"
-    jsonfile "^4.0.0"
-    universalify "^0.1.0"
-
 fs-extra@^7.0.1:
   version "7.0.1"
   resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-7.0.1.tgz#4f189c44aa123b895f722804f55ea23eadc348e9"
@@ -6378,16 +6374,16 @@ gatsby-remark-relative-images@^0.2.1:
     unist-util-select "^1.5.0"
 
 gatsby-source-filesystem@^2.0.26:
-  version "2.1.15"
-  resolved "https://registry.yarnpkg.com/gatsby-source-filesystem/-/gatsby-source-filesystem-2.1.15.tgz#ceb112df276b657acaeb79076f7c93633e1add3c"
-  integrity sha512-f5m+J0tzrpfz8Gr7/DDVldPZJeqBVpS6vTl80+rKFBYPzn+7/6cpb+NRkMb+NAIVOVch17K06kME0GFZ4Ypnuw==
+  version "2.1.18"
+  resolved "https://registry.yarnpkg.com/gatsby-source-filesystem/-/gatsby-source-filesystem-2.1.18.tgz#fcf80c62f243f4bfdb5ff4b17e8b0a79ace3730d"
+  integrity sha512-+LHqeDsK61F1BKiH1QGUNhZBH33tQVqB/iRw4AfKf/IlhfsJo5TzpzouAQv3aZXVj+5L05MSLmP9negHPGerag==
   dependencies:
     "@babel/runtime" "^7.5.5"
     better-queue "^3.8.10"
     bluebird "^3.5.5"
-    chokidar "2.1.8"
-    file-type "^10.11.0"
-    fs-extra "^5.0.0"
+    chokidar "3.0.2"
+    file-type "^12.2.0"
+    fs-extra "^8.1.0"
     gatsby-core-utils "^1.0.6"
     got "^7.1.0"
     md5-file "^3.2.3"