Bump to go 1.11.5

What does this MR do?

Update the go version used to build the project. It requires now 1.11.5, the latest version as of today.

Why was this MR needed?

On my local computer, I have go 1.11.5, and I can't build the project because the checksums were made with go 1.11.3. Go 1.11.5 is a Security release, so we should not stick to an older version.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug

What are the relevant issue numbers?

N/A

@fcatteau can you please take a look?