[ci]: fix things (#400)

for the spellcheck issue, the solution was to just bypass the system
package manager and use pip.

and the macos workaround is taken from here:
https://github.com/actions/setup-python/issues/577

Reviewed-on: https://codeberg.org/nsxiv/nsxiv/pulls/400
Reviewed-by: explosion-mental <explosion-mental@noreply.codeberg.org>

.github/workflows/build.yml

@@ -42,7 +42,8 @@ jobs:
       - name: dep
         run: |
           brew update
-          brew install imlib2 libx11 libxft libexif giflib webp
+          # see: https://github.com/actions/setup-python/issues/577
+          brew install imlib2 libx11 libxft libexif giflib webp || true
       - name: build
         run: |
           # libinotify-kqueue isn't available on homebrew