Add build support for arm64

[Firefishy]

THIS IS FOR COMMENT. Needs some clean-up / refactor work.

What I am changing

• ARM64 build of the gunicorn container
• Update GitHub Actions to latest releases
• Simplify the container tagging by using docker/metadata-action (also fix a case sensitive bug on fork)
• Add if statements to allow actions to cleanly run if forked
• Add dependabot to keep GHA updated

How I did it

• TBC

How you can test it

• https://github.com/Firefishy/titiler/actions/runs/7186402001/job/19571794840

Related Issues

• Provide a multiarch build (armhf/arm64) for the container #387

[vincentsarago]

can we do less than daily? I don't think the actions versions are super important that they deserve a daily check/update

[vincentsarago]

overall looks good 🙏

[Firefishy]

overall looks good 🙏

Cool. I'll refactor and clean it up.

GitHub actions check schedule I'll set to weekly. True update frequency is driven by when upstream have new major releases.

[vincentsarago]

@Firefishy can we merge this?

[vincentsarago]

rasterio still doesn't provide wheels for Mac OS AMD64 so this PR needs to wait for rasterio/rasterio-wheels#69

[Firefishy]

@vincentsarago Sorry, I have been away in South Africa for a month. I am now back and can get this PR into shape.

[vincentsarago]

I've commented out linux/arm64 because we still need rasterio to provide the wheels.

I'm going to merge this PR because I think it provides nice enhancements to the CI