Bump pandas from 1.2.0 to 1.2.1 (#2116)

Bumps [pandas](https://github.com/pandas-dev/pandas) from 1.2.0 to 1.2.1.
- [Release notes](https://github.com/pandas-dev/pandas/releases)
- [Changelog](https://github.com/pandas-dev/pandas/blob/master/RELEASE.md)
- [Commits](https://github.com/pandas-dev/pandas/compare/v1.2.0...v1.2.1)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -9,7 +9,7 @@ mozci==1.12.5
 numpy==1.19.5
 orjson==3.4.7
 ortools==8.1.8487
-pandas==1.2.0
+pandas==1.2.1
 psutil==5.8.0
 pydriller==1.12
 pyOpenSSL>=0.14  # Could not find a version that satisfies the requirement pyOpenSSL>=0.14; extra == "security" (from requests[security]>=2.7.0->libmozdata==0.1.43)