3.3.0 Release

• Update py38 image to 3.8.3
• Update py37 image to 3.7.7
• Update pip to 20.1.1
• Update pre-commit to 2.4.0
• Update tox to 3.15.1
• Update virtualenv to 20.0.21
• Add g++ 8.3.0
• Add gettext 0.19.8.1
• Add rsync 3.1.3