Remove non-standard increaseAllowance and decreaseAllowance from ERC20

[Amxx]

(See discussion in issue)

Fixes #4583

PR Checklist

• Tests
• Documentation
• Changeset entry (run npx changeset add)

[changeset-bot]

🦋 Changeset detected

Latest commit: 804ec79

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
openzeppelin-solidity	Major

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[frangio]

Should we add any documentation about the existence of increase/decreaseAllowance in previous versions?

[frangio]

Regarding documentation, my thinking was that we'd want to document for wallets that there is an alternative way to change allowance and any protections to approve should also be used with increaseAllowance. After discussing this, we don't think our documentation is the best place for this warning, and we're considering publishing a blog post about it.

[mcmoodoo]

Should we add any documentation about the existence of increase/decreaseAllowance in previous versions?

We definitely shoud. I came here because the official open zeppelin docs say that the functions exist:

Yet, I couldn't find them in the source code, hence posting here!

[ernestognw]

Should we add any documentation about the existence of increase/decreaseAllowance in previous versions?

We definitely shoud. I came here because the official open zeppelin docs say that the functions exist:

Yet, I couldn't find them in the source code, hence posting here!

You're looking at v4 sir. Please change the documentation version to 5.x 😄