linux: make python 3.9 default

Author: blarfoon

.github/workflows/all_os.yml

@@ -139,7 +139,10 @@ jobs:
           rustc --version
           cargo --version
       - name: Install Python 3.9
-        run: yum install -y python39
+        run: |
+          yum install -y python39
+          # Set python3.9 as default for node-gyp
+          npm config set python /usr/bin/python3.9
       - name: Prepare
         run: |
           source "$HOME/.cargo/env"