Use canonical link for all RFC references

[jonasfj]

We should be consistent in what resources we link to when linking to RFCs.

[HamdaanAliQuatil]

RFC Editor provides the canonical link we plan to use throughout the repository - https://www.rfc-editor.org/

[Ashutosh7788]

Hi! I’d like to work on this issue. Could you please assign it to me?

[HamdaanAliQuatil]

Hey @Ashutosh7788 👋 assigned this to you. Feel free to reach out in case of any blockers 🚀

[Ashutosh7788]

Thank you

[Arunpandey1234]

Hi! I'm a Flutter developer and this looks like a good first issue to get started with open-source. I'd love to work on this. Could you please assign it to me?

[AquibAquil]

I'd like to work on this issue. Is anyone currently assigned to it, or would it be okay if I take it up?

[HamdaanAliQuatil]

@Arunpandey1234 @AquibAquil, you may start working on this. Please raise small PRs - ideally changes to 1 file in 1 PR