format code in prs (#1166)

.github/workflows/format-code.yml

@@ -0,0 +1,20 @@
+name: format code
+on:
+  pull_request:
+
+jobs:
+  format-code:
+    name: Format Code
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dotnet-format
+        run: dotnet tool install -g dotnet-format
+      - name: Format Code
+        run: dotnet format
+
+      # actions/checkout fetches only a single commit in a detached HEAD state. Therefore
+      # we need to pass the current branch, otherwise we can't commit the changes.
+      # GITHUB_HEAD_REF is the name of the head branch. GitHub Actions only sets this for PRs.
+      - name: Commit Formatted Code
+        run: ./scripts/commit-formatted-code.sh $GITHUB_HEAD_REF

scripts/commit-formatted-code.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+set -euo pipefail
+
+GITHUB_BRANCH="${1}"
+
+if [[ $(git status) == *"nothing to commit"* ]]; then
+    echo "Nothing to commit. All code formatted correctly."
+else
+    echo "Formatted some code. Going to push the changes."
+    git config --global user.name 'Sentry Github Bot'
+    git config --global user.email 'bot+github-bot@sentry.io'
+    git fetch
+    git checkout ${GITHUB_BRANCH}
+    git commit -am "Format code"
+    git push --set-upstream origin ${GITHUB_BRANCH}
+fi