Bump pip from 21.3.1 to 25.3

Bumps [pip](https://github.com/pypa/pip) from 21.3.1 to 25.3.
- [Changelog](https://github.com/pypa/pip/blob/main/NEWS.rst)
- [Commits](pypa/pip@21.3.1...25.3)

---
updated-dependencies:
- dependency-name: pip
  dependency-version: '25.3'
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements-bootstrap-bionic.txt

@@ -1,3 +1,3 @@
-pip==21.3.1
+pip==25.3
 setuptools==49.2.1
 wheel==0.37.0

requirements-bootstrap.txt

@@ -1,3 +1,3 @@
-pip==24.1
+pip==25.3
 setuptools==70.1.1
 wheel==0.43.0