chore(ci): split off coverage workflow (#1944)

In #1936 we observed that
because we are using `pull_request_target` without a specific reference,
we are not in fact checking out the PR branch. This PR splits the
workflow into two, one only to run badger CI tests, and the other to run
tests & report coverage results (using pr_target with the appropriate
commit). This has the benefit that any issues with coverage are isolated
to one workflow, which we could disable later if problems arise. This
does create duplication of compute (all tests run x2) but we are using
github hosted runners so we do not pay for this cost. This also aligns
with our dgraph repo workflow setup.

.github/workflows/ci-badger-tests-coverage.yml

@@ -0,0 +1,32 @@
+name: ci-badger-tests-coverage
+on:
+  pull_request_target:
+    branches:
+      - main
+      - 'release/v*'
+jobs:
+  badger-tests-coverage:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v3 # checkout merge commit
+        with:
+          ref: "refs/pull/${{ github.event.number }}/merge"
+      - name: Get Go Version
+        run: |
+          #!/bin/bash
+          GOVERSION=$({ [ -f .go-version ] && cat .go-version; })
+          echo "GOVERSION=$GOVERSION" >> $GITHUB_ENV
+      - name: Setup Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: ${{ env.GOVERSION }}
+      - name: Install Dependencies
+        run: make dependency
+      - name: Run Badger Tests
+        run: make test
+      - name: Install Goveralls
+        run: go install github.com/mattn/goveralls@latest
+      - name: Send Coverage Results
+        env:
+          COVERALLS_TOKEN: ${{ secrets.COVERALLSIO_TOKEN }}
+        run: goveralls -coverprofile=cover.out

.github/workflows/ci-badger-tests.yml

@@ -4,7 +4,7 @@ on:
     branches:
       - main
       - 'release/v*'
-  pull_request_target:
+  pull_request:
     branches:
       - main
       - 'release/v*'
@@ -28,9 +28,3 @@ jobs:
         run: make dependency
       - name: Run Badger Tests
         run: make test
-      - name: Install Goveralls
-        run: go install github.com/mattn/goveralls@latest
-      - name: Send Coverage Results
-        env:
-          COVERALLS_TOKEN: ${{ secrets.COVERALLSIO_TOKEN }}
-        run: goveralls -coverprofile=cover.out