Reduced CI job timeouts.

.github/workflows/ci.yml

@@ -278,7 +278,7 @@ jobs:
             cxxstd: "11,14,17,2a"
             os: macos-11
 
-    timeout-minutes: 60
+    timeout-minutes: 15
     runs-on: ${{matrix.os}}
     container: ${{matrix.container}}
 
@@ -515,6 +515,7 @@ jobs:
             addrmd: 64
             os: windows-2019
 
+    timeout-minutes: 15
     runs-on: ${{matrix.os}}
 
     steps: