build(deps): bump pip from 25.2 to 25.3 in /requirements

Bumps [pip](https://github.com/pypa/pip) from 25.2 to 25.3.
- [Changelog](https://github.com/pypa/pip/blob/main/NEWS.rst)
- [Commits](pypa/pip@25.2...25.3)

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

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

Author: dependabot[bot]

requirements/pip.txt

@@ -5,10 +5,10 @@
 #    make upgrade
 #
 wheel==0.45.1
-    # via -r requirements/pip.in
+    # via -r pip.in
 
 # The following packages are considered to be unsafe in a requirements file:
-pip==25.2
-    # via -r requirements/pip.in
+pip==25.3
+    # via -r pip.in
 setuptools==80.9.0
-    # via -r requirements/pip.in
+    # via -r pip.in