ci: Update doxygen to 1.9.5 and pin MinGW

[axic]

This should fix the lint job, but the go-windows job still fails. The last successful one used MinGW 11.2, and current 12.2 is installed. It seems to be a recent problem (see this). We may want to pin an older one or wait for some upstream fixes?

[codecov[bot]]

Codecov Report

Merging #674 (6148443) into master (05819e3) will not change coverage. The diff coverage is n/a.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #674 +/- ## ======================================= Coverage 93.17% 93.17% ======================================= Files 25 25 Lines 3779 3779 Branches 391 391 ======================================= Hits 3521 3521 Misses 147 147 Partials 111 111 ```