fix: Update generate.yaml

Author: ldetmer

.github/workflows/generate.yaml

@@ -36,7 +36,7 @@ jobs:
           sudo apt update
           sudo apt install python3
           echo "using $(python3 --version)"
-          curl https://bootstrap.pypa.io/pip/3.6/get-pip.py -o get-pip.py
+          curl -O https://raw.githubusercontent.com/pypa/get-pip/3a2fcd4fef4195df1916b16e4b2f34091c9bcee7/public/get-pip.py
           python3 get-pip.py
       - run: ./google-api-java-client-services/.github/workflows/generate.sh ${{ matrix.service }}
       - uses: googleapis/code-suggester@v2 # takes the changes from git directory