fix: use raw strings to prevent warnings about escape sequences in strings

[matawed]

Description

I know that this project doesn't claim to be compatible with Python 3.12, but since I'm using this project on a machine with this setup and I get the following warnings:

/tmp/Bazel.runfiles_4bm23prw/runfiles/rules_python++pip+athenacli_requirements_312_athenacli_py2_none_any_adafebae/site-packages/athenacli/main.py:207: SyntaxWarning: invalid escape sequence '\e'
  """
/tmp/Bazel.runfiles_4bm23prw/runfiles/rules_python++pip+athenacli_requirements_312_athenacli_py2_none_any_adafebae/site-packages/athenacli/packages/special/iocommands.py:120: SyntaxWarning: invalid escape sequence '\e'
  pattern = re.compile('(^\\\e|\\\e$)')
/tmp/Bazel.runfiles_4bm23prw/runfiles/rules_python++pip+athenacli_requirements_312_athenacli_py2_none_any_adafebae/site-packages/athenacli/packages/special/iocommands.py:216: SyntaxWarning: invalid escape sequence '\d'
  match = re.search('\\$\d+', query)
/tmp/Bazel.runfiles_4bm23prw/runfiles/rules_python++pip+athenacli_requirements_312_athenacli_py2_none_any_adafebae/site-packages/athenacli/packages/parseutils.py:18: SyntaxWarning: invalid escape sequence '\d'
  """
/tmp/Bazel.runfiles_4bm23prw/runfiles/rules_python++pip+athenacli_requirements_312_athenacli_py2_none_any_adafebae/site-packages/athenacli/completer.py:31: SyntaxWarning: invalid escape sequence '\$'

I thought this PR might be a quick fix for that.

Checklist

• I've added this contribution to the changelog.md.
• I've added my name to the AUTHORS file (or it's already there).