Bump yamllint from 1.25.0 to 1.26.0 in /.github/workflows

Bumps [yamllint](https://github.com/adrienverge/yamllint) from 1.25.0 to 1.26.0.
- [Release notes](https://github.com/adrienverge/yamllint/releases)
- [Changelog](https://github.com/adrienverge/yamllint/blob/master/CHANGELOG.rst)
- [Commits](adrienverge/yamllint@v1.25.0...v1.26.0)

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

Author: dependabot[bot]

.github/workflows/constraints.txt

@@ -1,4 +1,4 @@
 pip==20.3.3
 ansible-base==2.10.4
-yamllint==1.25.0
+yamllint==1.26.0
 ansible-lint==4.3.7