ci: delay cargo-gpu-backwards-compat to ensure long-running jobs go first

Author: Firestar99

.github/workflows/ci.yaml

@@ -206,6 +206,9 @@ jobs:
         run: cargo xtask test-build
 
   cargo-gpu-backwards-compat:
+    # The dependency is technically unnecessary, this is just to delay the launch of this job, so that github prefers
+    # launching long-running jobs first. Currently, these jobs take only about 7min compared to 22min of others.
+    needs: [cargo-deny]
     strategy:
       fail-fast: false
       matrix: