freeze.py: Remove `3.6`
The 3.6 lockfile was removed in but freeze.py wasn't updated
@@ -118,7 +118,7 @@ if __name__ == "__main__":
"py",
nargs="*",
help="Python version(s) to update and freeze",
- default=("2.7", "3.6", "3.7", "3.8", "3.9"),
+ default=("2.7", "3.7", "3.8", "3.9"),
)
args = parser.parse_args()
default_py = "3.7"
