build-and-deploy: fix the run-name for MSYS builds

[dscho]

Seems that the ${{ ... }} construct is not recursive: embedding it within itself won't have the inner one expanded. In other words, triggering an i686 build of the mintty package resulted in this very ugly title:

Build and deploy mintty (${{ inputs.architecture }})

Let's avoid that by using the format() function.

[rimrul]

Why did we have that nested structure to begin with? To prevent empty parantheses when inputs.architecture is unset? Is that an expected situation?

[dscho]

Why did we have that nested structure to begin with? To prevent empty parantheses when inputs.architecture is unset? Is that an expected situation?

Indeed, to prevent empty parentheses, and it is quite common for inputs.architecture to be unset: that's the case for all MINGW builds.