actions: limit secheduled workflows to our main repo

Only run scheduled workflows on the main repository; prevents people
from using build minutes on their forks.

.github/workflows/benchmark.yml

@@ -11,6 +11,10 @@ jobs:
   # targets and their details.  Then we build either in a docker container
   # (Linux) or on the actual hosts (macOS, Windows).
   build:
+    # Only run scheduled workflows on the main repository; prevents people
+    # from using build minutes on their forks.
+    if: github.repository == 'libgit2/libgit2'
+
     strategy:
       matrix:
         platform:

.github/workflows/codeql.yml

@@ -10,6 +10,10 @@ env:
 
 jobs:
   analyze:
+    # Only run scheduled workflows on the main repository; prevents people
+    # from using build minutes on their forks.
+    if: github.repository == 'libgit2/libgit2'
+
     name: Analyze
     runs-on: ubuntu-latest
 

.github/workflows/nightly.yml

@@ -15,6 +15,10 @@ jobs:
   # targets and their details.  Then we build either in a docker container
   # (Linux) or on the actual hosts (macOS, Windows).
   build:
+    # Only run scheduled workflows on the main repository; prevents people
+    # from using build minutes on their forks.
+    if: github.repository == 'libgit2/libgit2'
+
     strategy:
       matrix:
         platform:
@@ -321,6 +325,10 @@ jobs:
       shell: bash
 
   coverity:
+    # Only run scheduled workflows on the main repository; prevents people
+    # from using build minutes on their forks.
+    if: github.repository == 'libgit2/libgit2'
+
     name: Coverity
     runs-on: ubuntu-latest
     steps: