Bump pandas from 1.1.0 to 1.1.1

Bumps [pandas](https://github.com/pandas-dev/pandas) from 1.1.0 to 1.1.1.
- [Release notes](https://github.com/pandas-dev/pandas/releases)
- [Changelog](https://github.com/pandas-dev/pandas/blob/master/RELEASE.md)
- [Commits](pandas-dev/pandas@v1.1.0...v1.1.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

requirements.txt

@@ -2,7 +2,7 @@
 appdirs==1.4.4
 freezegun==0.3.15
 numpy==1.19.1
-pandas==1.1.0
+pandas==1.1.1
 pytablewriter[html]==0.56.1
 pytest==6.0.1
 pytest-cov==2.10.1