Fix flag name

.github/workflows/ci.yml

@@ -57,6 +57,14 @@ jobs:
       - name: Collect coverage
         run: dotnet test --no-build -c Debug -f netcoreapp3.1 src/StripeTests/StripeTests.csproj /p:CollectCoverage=true /p:CoverletOutputFormat=opencover /p:ExcludeByAttribute=CompilerGenerated
 
+      - name: Get branch name (merge)
+        if: github.event_name != 'pull_request'
+        run: echo "commitBranch=$(echo ${GITHUB_REF#refs/heads/} | tr / -)" >> $GITHUB_ENV
+
+      - name: Get branch name (pull request)
+        if: github.event_name == 'pull_request'
+        run: echo "commitBranch=$(echo ${GITHUB_HEAD_REF} | tr / -)" >> $GITHUB_ENV
+
       - name: Send code coverage report to coveralls.io
         run: |
           dotnet tool run csmacnz.Coveralls \
@@ -68,11 +76,10 @@ jobs:
             --commitBranch $commitBranch \
             --commitAuthor $commitAuthor \
             --jobId $jobId \
-            --pullRequestId $pullRequestId
+            --pullRequest $pullRequestId
         env:
           COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
           commitId: ${{ github.sha }}
-          commitBranch: ${{ github.ref }}
           commitAuthor: ${{ github.actor }}
           jobId: ${{ github.run_id }}
           pullRequestId: ${{ github.event.pull_request.number }}