Remove ppc64le and s390x from building

Doesn't seem to be demand for them, plus the ppc64le builds keep timing out now. If there's demand we'll need to figure out a new way to incorporate them.

Author: robxu9

.github/workflows/build.yml

@@ -50,7 +50,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        arch: [armv6, armv7, aarch64, ppc64le, s390x]
+        arch: [armv6, armv7, aarch64]
     steps:
       - uses: actions/checkout@v3
       - uses: uraimo/run-on-arch-action@v2.5.0
@@ -113,7 +113,7 @@ jobs:
         with:
           path: artifacts
       - name: make executable
-        run: chmod +x artifacts/*
+        run: chmod +x artifacts/*/*
       - name: create release
         uses: softprops/action-gh-release@v1
         with: