Fix ggshield retrieval with proxy

[sevbch]

Context

Leveraging help from #79. (Thank you @GabrielCousin!)

This PR tentatively addresses certificate errors encountered by customers when installing the extension.

Error logs looked like this:

2025-04-23 22:03:04.615 [error] Activating extension gitguardian-secret-security.gitguardian failed due to an error:
2025-04-23 22:03:04.615 [error] Error: unable to get local issuer certificate
...

or

2025-04-22 17:39:09.130 [error] Activating extension gitguardian-secret-security.gitguardian failed due to an error:
2025-04-22 17:39:09.131 [error] Error: self signed certificate in certificate chain
...

What has been done

• Use axios instead of sync-request lib to make HTTP calls to github API
• Use param rejectUnauthorized from axios to disable SSL checks when option "allow self-signed certificate" is checked on the extension.
• Remove getGGShieldLatestVersion as it's not used anymore.
• Bump prettier version in pre-commit as it was not up-to-date with typescript version in this repo.

Best reviewed commit by commit.

Validation

I tried validating this using mitmproxy. Unfortunately I wasn't able to tweak it to make ggshield-download step fail on SSL certificate grounds.

So I haven't been able to confirm this line will fix encountered issues with proxy.
However, please note that this confirms the fix should work. So I think we can have a good confidence it will work.

Also, I was able to validate locally that changes here don't affect the standard behavior of the extension.

• checkout this branch
• check or un-check param "allow self-signed certificate" in the extension (both should work)
• delete ggshield-internal folder if it exists
• launch the extension in debug mode
• You can see in debug console the ggshield installation logs. If you add a secret somewhere it is well detected.

In conclusion,

• best case: this PR adresses the proxy scenario
• worst case: it doesn't but we'll have at least updated code to use a more standard lib for https calls.

PR check list

• As much as possible, the changes include tests
• If the changes affect the end user (new feature, behavior change, bug fix) then the PR has a changelog entry.

[salome-voltz]

Works for me ! thank you for the changes 🙏

I just have some minor remarks