Update the inset gallery example

[michaelgrund]

Description of proposed changes

Increase the margin pen size of the inset box since after updating to GMT 6.2.0rc1 it appears to be too thin.

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If adding new functionality, add an example to docstrings or tutorials.

Slash Commands

You can write slash commands (/command) in the first line of a comment to perform
specific operations. Supported slash commands are:

• /format: automatically format and lint the code
• /test-gmt-dev: run full tests on the latest GMT development version

[core-man]

Looks great~

[maxrjones]

Do you think that the inset box pen thickness is universally too thin with 6.2.0rc1, or just in this case since the pen color is not very bold? If it's a universal problem, we could try to fix the auto-scaling on the GMT side before 6.2.0.

[willschlitzer]

Do you think that the inset box pen thickness is universally too thin with 6.2.0rc1, or just in this case since the pen color is not very bold? If it's a universal problem, we could try to fix the auto-scaling on the GMT side before 6.2.0.

I agree that the inset box thickness is too thin on 6.2rc1, as it looks too thin on both the light yellow border and the black border in the tutorial examples.

[willschlitzer]

Can't say I notice that much of a difference between red and red3, but I think thickening the inset border is a smart move.

[michaelgrund]

Do you think that the inset box pen thickness is universally too thin with 6.2.0rc1, or just in this case since the pen color is not very bold? If it's a universal problem, we could try to fix the auto-scaling on the GMT side before 6.2.0.

So far, I only noticed it in this example.

[michaelgrund]

Can't say I notice that much of a difference between red and red3, but I think thickening the inset border is a smart move.

It's not a big difference, only looks a little bit more modern in my opinion 😄 , however, we could also leave it as is.

[maxrjones]

FYI, the PR at GenericMappingTools/gmt#5265 will revert the default behavior for pen with +p to the 6.1 standard. Of course, this doesn't prevent setting it manually anyways as done here.