Bump idna from 2.9 to 3.7 in /__tests__/data (#843)

Bumps [idna](https://github.com/kjd/idna) from 2.9 to 3.7.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.rst)
- [Commits](https://github.com/kjd/idna/compare/v2.9...v3.7)

---
updated-dependencies:
- dependency-name: idna
  dependency-type: direct:production
...

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

__tests__/data/requirements-linux.txt

@@ -1,7 +1,7 @@
 certifi==2020.6.20
 chardet==3.0.4
 docutils==0.16
-idna==2.10
+idna==3.7
 Kivy==2.0.0rc3
 Kivy-Garden==0.1.4
 packaging==20.7

__tests__/data/requirements.txt

@@ -8,7 +8,7 @@ docutils==0.16
 
 future==0.18.2; python_version >= '2.6' and python_version not in '3.0, 3.1, 3.2'
 
-idna==2.9
+idna==3.7
 
 itsdangerous==1.1.0