Return current object in SetContainer

[Component] [DependencyInjection] $this is missing in the setContainer function.  It broke my code in the following example:



| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | none
| License       | MIT
| Doc PR        | none