[rlgl] Add unsigned int to rlSetUniform

[spevnev]

Please, before submitting a new issue verify and check:

• I tested it on latest raylib version from master branch
• I checked there is no similar issue already reported
• I checked the documentation on the wiki
• My code has no errors or misuse of raylib

Issue description

rlSetUniform doesn't provide a way to set unsigned uniform, i.e. no way to call glUniform1uiv, glUniform2uiv, glUniform3uiv, glUniform4uiv.

Environment

Computer shader with OpenGL4.3

[raysan5]

@spevnev Is this request intended to address a specific use-case? Or is it just for completion?

[spevnev]

My use-case is having uniform uint length; in compute shader. It just makes sense to have it unsigned rather than signed.