Bump pip from 9.0.1 to 21.1 in /integration

Bumps [pip](https://github.com/pypa/pip) from 9.0.1 to 21.1.
- [Release notes](https://github.com/pypa/pip/releases)
- [Changelog](https://github.com/pypa/pip/blob/main/NEWS.rst)
- [Commits](pypa/pip@9.0.1...21.1)

---
updated-dependencies:
- dependency-name: pip
  dependency-type: direct:production
...

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

Author: dependabot[bot]

integration/requirements.txt

@@ -4,7 +4,7 @@ jupyter_client==7.1.0
 nbconvert==6.3.0
 nbformat==5.1.3
 numpy==1.21.0
-pip==9.0.1; python_version >= '3.6'
+pip==21.1; python_version >= '3.6'
 pytest==5.2.0
 pytest-timeout==1.3.3
 pytest-xdist==1.30.0