Add 60 minute timeout to build step of macos-build matrix job

Author: simonjbeaumont

.github/workflows/swift_package_test.yml

@@ -139,6 +139,7 @@ jobs:
         run: ${{ inputs.macos_pre_build_command }}
       - name: Build / Test
         run: ${{ inputs.macos_build_command }}
+        timeout-minutes: 60
 
   linux-build:
     name: Linux (${{ matrix.swift_version }} - ${{ matrix.os_version }})