main: drop Python 2 check

Python 2 can't even parse this code anymore due to syntax changes,
so there's no point in checking for it explicitly.

Bug: 302871152
Change-Id: I9852ace5f5079d037c60fd3ac490d77e074e6875
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/389434
Commit-Queue: Mike Frysinger <vapier@google.com>
Reviewed-by: Aravind Vasudevan <aravindvasudev@google.com>
Tested-by: Mike Frysinger <vapier@google.com>

main.py

@@ -86,27 +86,19 @@
 MIN_PYTHON_VERSION_SOFT = (3, 6)
 MIN_PYTHON_VERSION_HARD = (3, 6)
 
-if sys.version_info.major < 3:
+if sys.version_info < MIN_PYTHON_VERSION_HARD:
     logger.error(
-        "repo: error: Python 2 is no longer supported; "
+        "repo: error: Python version is too old; "
         "Please upgrade to Python %d.%d+.",
         *MIN_PYTHON_VERSION_SOFT,
     )
     sys.exit(1)
-else:
-    if sys.version_info < MIN_PYTHON_VERSION_HARD:
-        logger.error(
-            "repo: error: Python 3 version is too old; "
-            "Please upgrade to Python %d.%d+.",
-            *MIN_PYTHON_VERSION_SOFT,
-        )
-        sys.exit(1)
-    elif sys.version_info < MIN_PYTHON_VERSION_SOFT:
-        logger.error(
-            "repo: warning: your Python 3 version is no longer supported; "
-            "Please upgrade to Python %d.%d+.",
-            *MIN_PYTHON_VERSION_SOFT,
-        )
+elif sys.version_info < MIN_PYTHON_VERSION_SOFT:
+    logger.error(
+        "repo: warning: your Python version is no longer supported; "
+        "Please upgrade to Python %d.%d+.",
+        *MIN_PYTHON_VERSION_SOFT,
+    )
 
 KEYBOARD_INTERRUPT_EXIT = 128 + signal.SIGINT
 MAX_PRINT_ERRORS = 5