Bump tox from 4.20.0 to 4.21.0

Bumps [tox](https://github.com/tox-dev/tox) from 4.20.0 to 4.21.0.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/main/docs/changelog.rst)
- [Commits](tox-dev/tox@4.20.0...4.21.0)

---
updated-dependencies:
- dependency-name: tox
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

CI/requirements_ci.in

@@ -2,4 +2,4 @@ bump-my-version==0.26.1
 coveralls==4.0.1
 pip==24.2.0
 flit==3.9.0
-tox==4.20.0
+tox==4.21.0

CI/requirements_ci.txt

@@ -199,9 +199,9 @@ docutils==0.20.1 \
     --hash=sha256:96f387a2c5562db4476f09f13bbab2192e764cac08ebbf3a34a95d9b1e4a59d6 \
     --hash=sha256:f08a4e276c3a1583a86dce3e34aba3fe04d02bba2dd51ed16106244e8a923e3b
     # via flit
-filelock==3.15.4 \
-    --hash=sha256:2207938cbc1844345cb01a5a95524dae30f0ce089eba5b00378295a17e3e90cb \
-    --hash=sha256:6ca1fffae96225dab4c6eaf1c4f4f28cd2568d3ec2a44e15a08520504de468e7
+filelock==3.16.1 \
+    --hash=sha256:2082e5703d51fbf98ea75855d9d5527e33d8ff23099bec374a134febee6946b0 \
+    --hash=sha256:c249fbfcd5db47e5e2d6d62198e565475ee65e4831e2561c8e313fa7eb961435
     # via
     #   tox
     #   virtualenv
@@ -231,9 +231,9 @@ packaging==24.1 \
     # via
     #   pyproject-api
     #   tox
-platformdirs==4.2.2 \
-    --hash=sha256:2d7a1657e36a80ea911db832a8a6ece5ee53d8de21edd5cc5879af6530b1bfee \
-    --hash=sha256:38b7b51f512eed9e84a22788b4bce1de17c0adb134d6becb09836e37d8654cd3
+platformdirs==4.3.6 \
+    --hash=sha256:357fb2acbc885b0419afd3ce3ed34564c13c9b95c89360cd9563f73aa5e2b907 \
+    --hash=sha256:73e575e1408ab8103900836b97580d5307456908a03e92031bab39e4554cc3fb
     # via
     #   tox
     #   virtualenv
@@ -350,9 +350,9 @@ pygments==2.18.0 \
     --hash=sha256:786ff802f32e91311bff3889f6e9a86e81505fe99f2735bb6d60ae0c5004f199 \
     --hash=sha256:b8e6aca0523f3ab76fee51799c488e38782ac06eafcf95e7ba832985c8e7b13a
     # via rich
-pyproject-api==1.7.1 \
-    --hash=sha256:2dc1654062c2b27733d8fd4cdda672b22fe8741ef1dde8e3a998a9547b071eeb \
-    --hash=sha256:7ebc6cd10710f89f4cf2a2731710a98abce37ebff19427116ff2174c9236a827
+pyproject-api==1.8.0 \
+    --hash=sha256:3d7d347a047afe796fd5d1885b1e391ba29be7169bd2f102fcd378f04273d228 \
+    --hash=sha256:77b8049f2feb5d33eefcc21b57f1e279636277a8ac8ad6b5871037b243778496
     # via tox
 python-dotenv==1.0.1 \
     --hash=sha256:e324ee90a023d808f1959c46bcbc04446a10ced277783dc6ee09987c37ec10ca \
@@ -393,9 +393,9 @@ tomlkit==0.13.0 \
     --hash=sha256:08ad192699734149f5b97b45f1f18dad7eb1b6d16bc72ad0c2335772650d7b72 \
     --hash=sha256:7075d3042d03b80f603482d69bf0c8f345c2b30e41699fd8883227f89972b264
     # via bump-my-version
-tox==4.20.0 \
-    --hash=sha256:21a8005e3d3fe5658a8e36b8ca3ed13a4230429063c5cc2a2fdac6ee5aa0de34 \
-    --hash=sha256:5b78a49b6eaaeab3ae4186415e7c97d524f762ae967c63562687c3e5f0ec23d5
+tox==4.21.0 \
+    --hash=sha256:693ac51378255d34ad7aab6dd2ce9ab6a1cf1924eb930183fde850ad503b681d \
+    --hash=sha256:e64dd9847ff3a7ec90368be412d7efe61a39caf043222ffbe9ad638ea435f6f6
     # via -r CI/requirements_ci.in
 typing-extensions==4.12.2 \
     --hash=sha256:04e5ca0351e0f3f85c6853954072df659d0d13fac324d0072316b67d7794700d \
@@ -406,13 +406,14 @@ typing-extensions==4.12.2 \
     #   pydantic-core
     #   rich
     #   rich-click
+    #   tox
 urllib3==2.2.2 \
     --hash=sha256:a448b2f64d686155468037e1ace9f2d2199776e17f0a46610480d311f73e3472 \
     --hash=sha256:dd505485549a7a552833da5e6063639d0d177c04f23bc3864e41e5dc5f612168
     # via requests
-virtualenv==20.26.3 \
-    --hash=sha256:4c43a2a236279d9ea36a0d76f98d84bd6ca94ac4e0f4a3b9d46d05e10fea542a \
-    --hash=sha256:8cc4a31139e796e9a7de2cd5cf2489de1217193116a8fd42328f1bd65f434589
+virtualenv==20.26.6 \
+    --hash=sha256:280aede09a2a5c317e409a00102e7077c6432c5a38f0ef938e643805a7ad2c48 \
+    --hash=sha256:7345cc5b25405607a624d8418154577459c3e0277f5466dd79c49d5e492995f2
     # via tox
 wcmatch==8.5.2 \
     --hash=sha256:17d3ad3758f9d0b5b4dedc770b65420d4dac62e680229c287bf24c9db856a478 \