[L] Change in coreboot[main]: util/scripts: Improve update_submodules script

[Martin L Roth (Code Review)]

Attention is currently required from: Martin L Roth.

Hello build bot (Jenkins),

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/77580?usp=email

to look at the new patch set (#3).

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Verified+1 by build bot (Jenkins)

Change subject: util/scripts: Improve update_submodules script
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util/scripts: Improve update_submodules script

I recently tried to update the amd_blobs submodule with the script, and
it tried to check out origin/main instead of origin/master which would
have rolled the submodule pointer back one commit. the commit also added
another submodule that was previously staged. These issues prompted me
to fix this script so it wouldn't do unexpected things.

This adds a number of changes and fixes to the update_submodules script.
- Update the version to 2.00
- Make global variables uppercase
- Add pause function for warnings and errors
- Add debug functions and -D | --debug argument to enable them
- Add -b | --branch argument to allow branch to be specified
- Add -m | --min_days argument to specify the min time (30 day default)
- Split out functionality to find the branch name into a function
- If there are multiple valid branches, try to pick the newest
- Error out if no branches are valid
- Make local variables local
- Verify that nothing is staged that would get added accidentally
- Verify that the submodule being checked is clean
- Show when submodules are being fetched
- Get 12 digits of commit ID for initial and ending commits
- Print short date for initial & ending commits
- Don't update if the last update was more recent than min_days
- Make sure we're not updating to an older commit
- If there's only one new commit, don't say 'commits' (plurl)
- Print errors to stderr
- When there's any issue creating a commit, show how to fix it
- Disable some "Consider this" type warnings in shellcheck.

Signed-off-by: Martin Roth 
Change-Id: I39ae6799f2965e8421fb0ddfb463833b3f3be037
---
M util/scripts/update_submodules
1 file changed, 217 insertions(+), 55 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/80/77580/3