Make compiler-rt version match the clang version in the gitea action

.gitea/workflows/validate.yaml

@@ -18,7 +18,7 @@ jobs:
 
           # determine correct clang version and then install it
           apk update
-          RT_VERSION=$(apk add --simulate compiler-rt | grep -o "compiler-rt-[0-9]*" | grep -o "[0-9]*")
+          RT_VERSION=$(apk search -v compiler-rt | grep -o "compiler-rt-[0-9]*" | head -1 | grep -o "[0-9]*")
           apk add --no-cache llvm${RT_VERSION} clang${RT_VERSION} clang${RT_VERSION}-analyzer compiler-rt valgrind
 
           # Verify versions