CI: skip scheduled builds on forks

tracking bleeding edge changes with some rare platforms or modern
compilers on scheduled basis is not what usually forks do. let's
skip by default in forks, if some fork is interested, it might be
enabled locally

.github/workflows/cross-zoo.yml

@@ -90,6 +90,7 @@ jobs:
           }
         ]
     runs-on: ubuntu-latest
+    if: ${{ github.repository_owner == 'haproxy' }}
     steps:
     - name: install packages
       run: |

.github/workflows/fedora-rawhide.yml

@@ -14,6 +14,7 @@ jobs:
         cc: [ gcc, clang ]
     name: ${{ matrix.cc }}
     runs-on: ubuntu-latest
+    if: ${{ github.repository_owner == 'haproxy' }}
     container:
       image: fedora:rawhide
     steps: