Drop Python 2.7 support

Upstream IPython dropped it in version 6.0.0, in April 2017. I think it's fine to drop it here now.

Would also be good to use this opportunity to mark the release as 1.0.0.

HISTORY.txt

@@ -4,7 +4,7 @@ Changelog
 0.13.10 (unreleased)
 --------------------
 
-- Nothing changed yet.
+- Drop Python 2.7 compatibility.
 
 
 0.13.9 (2021-06-02)

ipdb/__main__.py

@@ -16,10 +16,7 @@
 from IPython.core.debugger import BdbQuit_excepthook
 from IPython.terminal.ipapp import TerminalIPythonApp
 from IPython.terminal.embed import InteractiveShellEmbed
-try:
-    import configparser
-except:
-    import ConfigParser as configparser
+import configparser
 
 
 def _get_debugger_cls():
@@ -255,11 +252,7 @@ def main():
     import sys
     import getopt
 
-    try:
-        from pdb import Restart
-    except ImportError:
-        class Restart(Exception):
-            pass
+    from pdb import Restart
 
     if sys.version_info >= (3, 7):
         opts, args = getopt.getopt(sys.argv[1:], 'mhc:', ['help', 'command='])

setup.py

@@ -30,7 +30,6 @@
       description="IPython-enabled pdb",
       long_description=long_description,
       classifiers=[
-        'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
@@ -58,7 +57,6 @@
           'setuptools',
       ],
       extras_require={
-          ':python_version == "2.7"': ['ipython >= 5.1.0, < 6.0.0', 'toml >= 0.10.2', 'decorator < 5.0.0'],
           # No support for python 3.0, 3.1, 3.2.
           # FTR, `decorator` is also a dependency of Ipython.
           ':python_version == "3.4"': ['ipython >= 6.0.0, < 7.0.0', 'toml >= 0.10.2', 'decorator < 5.0.0'],