chore: enhance bump script to default to a minor version bump (aws#4389)

* chore: enhance bump script to default to a minor version bump

Also supports any semVer string as input for scenarios where we want to release patches, major versions, etc.
Made a switch to use standard-version to create a commit at the end of the bump. standard-version also takes
care of the CHANGELOG generation now.

* use npx to execute standard-version

bump.sh

@@ -1,30 +1,34 @@
 #!/bin/bash
+# --------------------------------------------------------------------------------------------------
+#
+# This script is intended to be used to bump the version of the CDK modules, update package.json,
+# package-lock.json, and create a commit.
+#
+# to start a version bump, run:
+#     bump.sh <version | version Type>
+#
+# If a version is not provided, the 'minor' version will be bumped.
+# The version can be an explicit version _or_ one of:
+# 'major', 'minor', 'patch', 'premajor', 'preminor', 'prepatch', or 'prerelease'.
+#
+# --------------------------------------------------------------------------------------------------
 set -euo pipefail
-ver=${1:-}
-if [ -z "${ver}" ]; then
-  echo "usage: ./bump.sh <version>"
-  exit 1
-fi
+version=${1:-minor}
+
+echo "Starting ${version} version bump"
 
 export NODE_OPTIONS="--max-old-space-size=4096 ${NODE_OPTIONS:-}"
 
 /bin/bash ./install.sh
 
-npx lerna version --force-publish=* --no-git-tag-version --no-push ${ver}
-
-# Update CHANGELOG.md only at the root
-cat > /tmp/context.json <<HERE
-{
-  "version": "${ver}"
-}
-HERE
+npx lerna version ${version} --force-publish=* --no-git-tag-version --no-push
 
 # Another round of install to fix package-lock.jsons
 /bin/bash ./install.sh
 
-./node_modules/.bin/conventional-changelog -p angular -i CHANGELOG.md -s --context /tmp/context.json
-
 # align "peerDependencies" to actual dependencies after bump
 # this is technically only required for major version bumps, but in the meantime we shall do it in every bump
 /bin/bash scripts/fix-peer-deps.sh
 
+# Generate CHANGELOG and create a commit
+npx standard-version --release --skip.tag=true --commit-all

package.json

@@ -18,6 +18,7 @@
     "lerna": "^3.16.5",
     "nodeunit": "^0.11.3",
     "nyc": "^14.1.1",
+    "standard-version": "^7.0.0",
     "ts-jest": "^24.1.0",
     "tslint": "^5.20.0",
     "typescript": "~3.6.3"
@@ -26,6 +27,13 @@
     "type": "git",
     "url": "git://github.com/aws/aws-cdk"
   },
+  "standard-version": {
+    "releaseCommitMessageFormat": "{{currentTag}}",
+    "scripts": {
+      "prebump": "echo $(node -pe \"require('./lerna.json').version\")",
+      "precommit": "git add ."
+    }
+  },
   "license": "Apache-2.0",
   "author": {
     "name": "Amazon Web Services",