Don't force --show-source in .flake8 !

This was the cause of our flake8-your-pr issue!  It meant that as well
as `--format json` giving JSON output it also got polluted with the raw
string of the source line as well.

.flake8

@@ -1,6 +1,6 @@
 [flake8]
 # Show exactly where in a line the error happened
-show-source = True
+#show-source = True
 
 max-line-length = 120
 # Add _ as a builtin for localisation stuff

.github/workflows/pr-annotate-with-flake8.yml

@@ -24,6 +24,6 @@ jobs:
       with:
         python-version: 3.7
     - name: Annotate with Flake8
-      uses: "Athanasius/flake8-your-pr@master"
+      uses: "tayfun/flake8-your-pr@master"
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}