Run validation mode via docker run so the event name actually applies

Author: haseebmalik18

.github/workflows/e2e.yml

@@ -51,6 +51,9 @@ jobs:
             cp .e2e-action/dockerfile .e2e-action/Dockerfile
           fi
 
+      - name: Build the action image
+        run: docker build -t codejson-action .e2e-action
+
       - name: Link back to the pull request
         run: |
           echo "Testing [PR #${{ inputs.pr_number }}](https://github.com/DSACMS/automated-codejson-generator/pull/${{ inputs.pr_number }}) at \`${{ inputs.action_sha }}\`" >> "$GITHUB_STEP_SUMMARY"
@@ -59,27 +62,29 @@ jobs:
         run: cp e2e/fixtures/code.json.good code.json
 
       - name: Validate the good code.json
-        uses: ./.e2e-action
-        env:
-          # The action validates instead of generating when it sees a pull_request
-          # event. That is the only switch for this mode, so we set it directly.
-          GITHUB_EVENT_NAME: pull_request
-        with:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          BRANCH: main
+        run: |
+          # GITHUB_EVENT_NAME can't be set through uses:, so run the image ourselves
+          # to put the action in validation mode.
+          docker run --rm \
+            -e GITHUB_EVENT_NAME=pull_request \
+            -e GITHUB_ACTION=e2e \
+            -e INPUT_GITHUB_TOKEN=${{ secrets.GITHUB_TOKEN }} \
+            -v "${{ github.workspace }}:/github/workspace" \
+            codejson-action
 
       - name: Stage a broken code.json
         run: cp e2e/fixtures/code.json.broken code.json
 
       - name: Validate the broken code.json
         id: validate_broken
         continue-on-error: true
-        uses: ./.e2e-action
-        env:
-          GITHUB_EVENT_NAME: pull_request
-        with:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          BRANCH: main
+        run: |
+          docker run --rm \
+            -e GITHUB_EVENT_NAME=pull_request \
+            -e GITHUB_ACTION=e2e \
+            -e INPUT_GITHUB_TOKEN=${{ secrets.GITHUB_TOKEN }} \
+            -v "${{ github.workspace }}:/github/workspace" \
+            codejson-action
 
       - name: Assert the broken code.json was rejected
         run: |