ci: Drop python2

Author: KrystalDelusion

.github/actions/setup-build-env/action.yml

@@ -8,7 +8,7 @@ runs:
       shell: bash
       run: |
         sudo apt-get update
-        sudo apt-get install gperf build-essential bison flex libreadline-dev gawk tcl-dev libffi-dev git graphviz xdot pkg-config python python3 libboost-system-dev libboost-python-dev libboost-filesystem-dev zlib1g-dev
+        sudo apt-get install gperf build-essential bison flex libreadline-dev gawk tcl-dev libffi-dev git graphviz xdot pkg-config python3 libboost-system-dev libboost-python-dev libboost-filesystem-dev zlib1g-dev
 
     - name: Install macOS Dependencies
       if: runner.os == 'macOS'