Update pip

Author: ahosgood

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Updated Poetry to [2.3.2](https://github.com/python-poetry/poetry/releases/tag/2.3.2)
 - Updated Gunicorn to [25.0.1](https://github.com/benoitc/gunicorn/releases/tag/25.0.1)
 - Replaced the bundled Stylelint configuration with the [Stylelint configuration in TNA Frontend](https://github.com/nationalarchives/tna-frontend/blob/main/stylelint.config.js)
+- Updated pip to `26.0`
 
 ### Deprecated
 ### Removed

docker/tna-python/Dockerfile

@@ -73,7 +73,7 @@ ENV PIP_NO_CACHE_DIR=true \
 #    environment variable at build-time"
 # > docs.docker.com/build/building/variables
 # ==========================================
-ENV PIP_VERSION=25.3 \
+ENV PIP_VERSION=26.0 \
     POETRY_VERSION=2.3.2 \
     NVM_VERSION=0.40.4 \
     WSGI_GUNICORN_VERSION=25.0.1 \