improve error handling, save branch name for push

.github/workflows/sync-linguist.yml

@@ -8,7 +8,13 @@ jobs:
     - uses: actions/setup-go@v2
     - uses: actions/checkout@v2
     - name: Create a branch
-      run: git checkout -b feature/sync-linguist-$(date +%s)
+      id: branch
+      run: |
+        set -euo pipefail
+        IFS=$'\n\t'        
+        branch_name=$(feature/sync-linguist-$(date +%s))
+        git checkout -b $branch_name
+        echo "::set-output name=branch_name::$branch_name"
     - uses: actions/checkout@v2
       with:
         repository: github/linguist
@@ -19,7 +25,8 @@ jobs:
       # the `grep -v "-"` is to exclude any pre-release versions.
       # Linguist doesn't have any right now, but just in case.
       run: |
-        set -e
+        set -euo pipefail
+        IFS=$'\n\t'        
         cd .linguist
         latest=$(git tag --list | \
                     grep -v "-" | \ 
@@ -33,13 +40,14 @@ jobs:
     - name: Commit changes
       id: commit
       run: |
-        set -e
+        set -euo pipefail
+        IFS=$'\n\t'
         if [[ -n "$(git status --porcelain)" ]]; then
           git config user.name github-actions
           git config user.email github-actions@github.com
           git add .
           git commit -m "Updated Linguist to ${{ steps.linguist-release.outputs.linguist_version }}"
-          git push
+          git push --set-upstream origin ${{ steps.branch.outputs.branch_name }}
           echo "::set-output name=needs_pr::true"
         else
           echo "::set-output name=needs_pr::false"