chore: move yamllint config to pre-commit config (#205)

@rusty1s This PR aims to further improve the overall structure of the
repository by moving the yamllint configuration within the
`pre-commit-config.yaml` file.

The only snippet in which the `.yamllint.yml` file was being used was
the pre-commit config file. yamllint [allows to have a custom
configuration without a config
file](https://yamllint.readthedocs.io/en/stable/configuration.html#custom-configuration-without-a-config-file)
by using the `-d` flag. Using this feature, we add a serialized version
of the config in the args parameter of the pre-commit config.

Similar to pyg-team/pytorch_geometric#6776

.pre-commit-config.yaml

@@ -15,7 +15,8 @@ repos:
     rev: v1.29.0
     hooks:
       - id: yamllint
-        args: [-c=.yamllint.yml]
+        name: Lint yaml
+        args: [-d, '{extends: default, rules: {line-length: disable, document-start: disable, truthy: {level: error}, braces: {max-spaces-inside: 1}}}']
 
   - repo: https://github.com/regebro/pyroma
     rev: "4.2"