all: Remove Python 2.7 support.

Python 2.7 has been EOL since January 2020.

Ubuntu oldoldlts (Focal Fossa, 20.04) has Python 3.8.  Debian oldoldstable
(Buster, from 2019) has Python 3.7.  RHEL 8 (from 2019) has Python 3.6.

It's easier than ever to install a modern Python using uv.

Given this, it seems like a fine idea to drop Python 2.7 support.

Even though the build is not tested on Python as old as 3.3, I left
comments stating that "3.3+" is the baseline Python version.  However, it
might make sense to bump this to e.g., 3.10, the oldest Python 3 version
used during CI. Or, using uv or another method actually test on the oldest
Python interpreter that is desirable to support (uv goes back to Python 3.7
easily; in October 2025, the oldest supported Python interpreter version
will be 3.10)

Signed-off-by: Jeff Epler <jepler@gmail.com>

py/makeversionhdr.py

@@ -1,7 +1,7 @@
 """
 Generate header file with macros defining MicroPython version info.
 
-This script works with Python 2.6, 2.7, 3.3 and 3.4.
+This script works with Python 3.3+.
 """
 
 from __future__ import print_function
@@ -22,12 +22,6 @@ import subprocess
 #   "vX.Y.Z-preview.N.gHASH.dirty" -- building at any subsequent commit in the cycle
 #                                     with local changes
 def get_version_info_from_git(repo_path):
-    # Python 2.6 doesn't have check_output, so check for that
-    try:
-        subprocess.check_output
-    except AttributeError:
-        return None
-
     # Note: git describe doesn't work if no tag is available
     try:
         git_tag = subprocess.check_output(
@@ -57,12 +51,6 @@ def get_version_info_from_git(repo_path):
 
 
 def get_hash_from_git(repo_path):
-    # Python 2.6 doesn't have check_output, so check for that.
-    try:
-        subprocess.check_output
-    except AttributeError:
-        return None
-
     try:
         return subprocess.check_output(
             ["git", "rev-parse", "--short", "HEAD"],