add diff coverage badge

Author: samuelcolvin

.github/workflows/coverage.yaml

@@ -34,3 +34,12 @@ jobs:
           SMOKESHOW_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           SMOKESHOW_GITHUB_PR_HEAD_SHA: ${{ github.event.workflow_run.head_sha }}
           SMOKESHOW_AUTH_KEY: ${{ secrets.SMOKESHOW_AUTH_KEY }}
+
+      - run: smokeshow upload diff-coverage-html/diff-coverage.html
+        env:
+          SMOKESHOW_GITHUB_STATUS_DESCRIPTION: Diff Coverage
+          SMOKESHOW_GITHUB_COVERAGE_THRESHOLD: 95
+          SMOKESHOW_GITHUB_CONTEXT: diff-coverage
+          SMOKESHOW_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          SMOKESHOW_GITHUB_PR_HEAD_SHA: ${{ github.event.workflow_run.head_sha }}
+          SMOKESHOW_AUTH_KEY: ${{ secrets.SMOKESHOW_AUTH_KEY }}