CI: run forwards jobs only for votca org

Author: junghans

.github/workflows/create-pr.yml

@@ -7,6 +7,7 @@ on:
 jobs:
   PR:
     name: Create
+    if: github.repository_owner == 'votca'
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code

.github/workflows/forward-to-votca.yml

@@ -7,6 +7,7 @@ on:
 
 jobs:
   VOTCA:
+    if: github.repository_owner == 'votca'
     runs-on: ubuntu-latest
     steps:
       - name: Update submodule