Fetch tags of submodules

Some projects rely on tag to determine the published version number, so
this is needed for the community build to work properly.

Author: smarter

.github/workflows/ci.yaml

@@ -166,6 +166,7 @@ jobs:
         run: |
           git submodule sync
           git submodule update --init --recursive --jobs 7
+          git submodule foreach --recursive 'git fetch -f --tags'
           ./project/scripts/sbt "community-build/testOnly dotty.communitybuild.CommunityBuildTestA"
 
   community_build_b:
@@ -201,6 +202,7 @@ jobs:
         run: |
           git submodule sync
           git submodule update --init --recursive --jobs 7
+          git submodule foreach --recursive 'git fetch -f --tags'
           ./project/scripts/sbt "community-build/testOnly dotty.communitybuild.CommunityBuildTestB"
 
   test_sbt: