feat: return CID of flushed path from ipfs.files.flush (ipfs#2715)

* feat: return CID of flushed path from ipfs.files.flush
* fix: writing mfs files using offsets bigger than the file now works

BREAKING CHANGE:

Removes all `codec`/`format` options, everything is `dag-pb` now.

package.json

@@ -98,9 +98,9 @@
     "ipfs-bitswap": "^0.26.2",
     "ipfs-block": "~0.8.1",
     "ipfs-block-service": "~0.16.0",
-    "ipfs-http-client": "^40.2.0",
+    "ipfs-http-client": "^41.0.0",
     "ipfs-http-response": "~0.4.0",
-    "ipfs-mfs": "^0.14.0",
+    "ipfs-mfs": "^0.15.0",
     "ipfs-multipart": "^0.3.0",
     "ipfs-repo": "^0.30.0",
     "ipfs-unixfs": "^0.3.0",
@@ -204,7 +204,7 @@
     "execa": "^3.0.0",
     "form-data": "^3.0.0",
     "hat": "0.0.3",
-    "interface-ipfs-core": "^0.126.0",
+    "interface-ipfs-core": "^0.127.0",
     "ipfs-interop": "^0.2.0",
     "ipfsd-ctl": "^1.0.2",
     "libp2p-websocket-star": "~0.10.2",