CI: github: pin ARM development builds to Ubuntu 26.04

The ubuntu-latest-arm runner label does not exist, preventing ARM
development jobs from starting. Use ubuntu-26.04-arm instead, matching
the stable branch builds.

diff --git a/.github/matrix.py b/.github/matrix.py
index f7d5819e01d691cdad8c5c2630e42541bcf27a6e..87e7faeba26761f66479b4dc50cf4d597ceb5fb3 100755 (executable)
--- a/.github/matrix.py
+++ b/.github/matrix.py
@@ -179,7 +179,7 @@ def main(ref_name):
         os_i686 = "ubuntu-26.04"    # stable branch
     else:
         os = "ubuntu-latest"         # development branch
-        os_arm = "ubuntu-latest-arm" # development branch
+        os_arm = "ubuntu-26.04-arm" # development branch
         os_i686 = "ubuntu-latest"    # development branch
 
     TARGET = "linux-glibc"