CI: remove unnecessary variables and indirection

Drop the indirection - we don't need to checkout to custom location.
Thus we can drop the no longer used HOME and RTAG variables.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

.github/workflows/update-patches-doc.yaml

@@ -32,33 +32,19 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-
-      - name: "Get value from dispatch"
-        run: |
-          if [ -z "${RTAG}" ]; then
-            echo "RTAG=$GITHUB_SHA" >> $GITHUB_ENV
-            echo "RTAG=$RTAG"
-          fi
-
       - name: Checkout 'uazo/cromite' ${{ env.BRANCH }}
         uses: actions/checkout@v2
         with:
             repository: 'uazo/cromite'
             ref: ${{ github.event.inputs.rtag }}
-            path: 'cromite'
             fetch-depth: 1
 
       - name: Generate patches doc
         run: |
-          export HOME=$GITHUB_WORKSPACE
-
-          bash ~/cromite/tools/extract-all-patch-data.sh ~/cromite/build/patches
+          bash ./tools/extract-all-patch-data.sh ./build/patches
 
       - name: Check differences CHANGES=${{ env.CHANGES }}
         run: |
-          export HOME=$GITHUB_WORKSPACE
-
-          cd ~/cromite
           CHANGES=0 && git diff --quiet || CHANGES=1
           echo "CHANGES=$CHANGES" >> $GITHUB_ENV