Bump matcher dependency to latest version

Changes:
  63f1110 Make argument to featureValueOf dynamic (#164)
  71eeaee Make the item argument to Match dynamic again (#163)
  2071cfd Add types to more parameters (#162)
  5d52720 Allow null-safe code to do `same(null)`. (#161)
  05db35c Delete .test_config (#160)
  e8b4964 remove redundant experiment (#159)
  48fe280 Bump SDK constraints for pub (#158)
  225cc13 allow the 2.12 prerelease sdks (#157)
  b9ce574 Prepare for the 2.11 dev SDKs (#156)
  fe4e68a Update .travis.yml
Change-Id: I90c8d9d2f21d6454f1ace977deb9efec0d29d93d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/177881
Reviewed-by: David Morgan <[email protected]>
Commit-Queue: Ivan Inozemtsev <[email protected]>

.dart_tool/package_config.json

@@ -396,7 +396,7 @@
       "name": "matcher",
       "rootUri": "../third_party/pkg/matcher",
       "packageUri": "lib/",
-      "languageVersion": "2.10"
+      "languageVersion": "2.12"
     },
     {
       "name": "meta",

DEPS

@@ -122,7 +122,7 @@ vars = {
   "logging_rev": "e2f633b543ef89c54688554b15ca3d7e425b86a2",
   "markupsafe_rev": "8f45f5cfa0009d2a70589bcda0349b8cb2b72783",
   "markdown_rev": "6f89681d59541ddb1cf3a58efbdaa2304ffc3f51",
-  "matcher_rev": "9cae8faa7868bf3a88a7ba45eb0bd128e66ac515",
+  "matcher_rev": "63f1110a657fb5e2dc378db8895fef7b0a13ab30",
   "mime_rev": "c931f4bed87221beaece356494b43731445ce7b8",
   "mockito_rev": "d39ac507483b9891165e422ec98d9fb480037c8b",
   "mustache_rev": "664737ecad027e6b96d0d1e627257efa0e46fcb1",