Updated addVariable() and updateVariable()

[c33s]

updated addVariable() and updateVariable() to match current gitlab api (added $protected $environment_scope`)

• https://docs.gitlab.com/ee/api/project_level_variables.html#create-variable
• https://docs.gitlab.com/ee/api/project_level_variables.html#update-variable

[c33s]

an idea also would be to do some input validation with webmozart/assert

Assert::nullOrBoolean($protected)
Assert::nullOrString($environment_scope)

[c33s]

@m1guelpf what about the suggestion to add assert? this would add a new dependency to the code but will improve the error detection. but it is a very stable dependency (26M downloads ). it is from @webmozart inpired by beberlei/assert.

[fbourigault]

We started using OptionsResolver to validate filters/payloads.

[c33s]

anything missing from my side that you can merge this PR?

[m1guelpf]

Again, 👍
@fbourigault Your opinion?

[fbourigault]

Thank you!