ci: bump idna from 3.14 to 3.15 in /requirements (#23)

Bumps [idna](https://github.com/kjd/idna) from 3.14 to 3.15.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.md)
- [Commits](kjd/idna@v3.14...v3.15)

---
updated-dependencies:
- dependency-name: idna
  dependency-version: '3.15'
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements/release.txt

@@ -286,9 +286,9 @@ id==1.6.1 \
     --hash=sha256:d0732d624fb46fd4e7bc4e5152f00214450953b9e772c182c1c22964def1a069 \
     --hash=sha256:f5ec41ed2629a508f5d0988eda142e190c9c6da971100612c4de9ad9f9b237ca
     # via twine
-idna==3.14 \
-    --hash=sha256:466d810d7a2cc1022bea9b037c39728d51ae7dad40d480fc9b7d7ecf98ba8ee3 \
-    --hash=sha256:e677eaf072e290f7b725f9acf0b3a2bd55f9fd6f7c70abe5f0e34823d0accf69
+idna==3.15 \
+    --hash=sha256:048adeaf8c2d788c40fee287673ccaa74c24ffd8dcf09ffa555a2fbb59f10ac8 \
+    --hash=sha256:ca962446ea538f7092a95e057da437618e886f4d349216d2b1e294abfdb65fdc
     # via requests
 jaraco-classes==3.4.0 \
     --hash=sha256:47a024b51d0239c0dd8c8540c6c7f484be3b8fcf0b2d85c13825780d3b3f3acd \