Add messageRetentionDuration to PubSub Topic

[Feggah]

Description of your changes

Fixes #422

I have:

• Read and followed Crossplane's contribution process.
• Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

• Managing the messageRetentionDuration field using the managed resource
• Adding tests

Important note for reviewers

Currently, it is possible to use a fractional number in the messageRetentionDuration field, for example: 1200.5s.

This will cause an update-loop in the managed resource, because the API returns the value as 1200.500s, which is "different" in our comparisons.

This bug won't appear if the platform builder uses an integer, for example, 1200s. In this case, the GCP API will return 1200s and it will be considered up to date.

I decided to not include this parser to include zeros/exclude zeros after the dot before the comparisons for simplicity for now, but if you think it is crucial for this feature, please request changes :)

[turkenh]

Currently, it is possible to use a fractional number in the messageRetentionDuration field, for example: 1200.5s.

This will cause an update-loop in the managed resource, because the API returns the value as 1200.500s, which is "different" in our comparisons.

This bug won't appear if the platform builder uses an integer, for example, 1200s. In this case, the GCP API will return 1200s and it will be considered up to date.

I decided to not include this parser to include zeros/exclude zeros after the dot before the comparisons for simplicity for now, but if you think it is crucial for this feature, please request changes :)

I don't think it is crucial, but also I believe we can just parse them as duration and compare https://go.dev/play/p/wKfeyJxpOIZ ?

[Feggah]

I don't think it is crucial, but also I believe we can just parse them as duration and compare https://go.dev/play/p/wKfeyJxpOIZ ?

Sure, I didn't think about this solution @turkenh. Thanks for the tip!

Added the suggestion 🙂

[turkenh]

LGTM, thanks @Feggah!