fix: Sets some http headers to use constants
What does this MR do?
This sets a few common HTTP headers to use constants to avoid spelling mistakes, as a starting point just Accept and Content-Type, if this ends up being the right direction then subsequent MRs can be raised to include more headers.
- Accept
- Content-Type
In this PR I've just added these to the common
package, but in some cases it doesn't make it clear that these are http-related values, so not sure if we'd put this either in it's own package, or include a prefix in each header name?
Why was this MR needed?
To allow the compiler to pick up spelling mistakes.