[github-actions] Use newer cython version (macOS/Linux)

.github/workflows/build.yml

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index d054366..b740952 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -12,7 +12,7 @@
     - name: install dependencies
       run: |
           sudo apt-get update
-          sudo apt-get install cython3
+          pip install cython
     - name: prepare environment
       run: |
           echo "target_triplet=`gcc -dumpmachine`" >> $GITHUB_ENV
@@ -74,7 +74,7 @@
           else
             brew install libtool autoconf automake pkgconfig
           fi
-          pip3 install cython==0.29.24
+          pip3 install cython
       shell: bash
     - name: fetch libplist
       uses: dawidd6/action-download-artifact@v2