[build] update FFmpeg to 4.3.2 for binary wheels

Mention Python 3.10 compatibility, drop Python 3.6.

.github/workflows/tests.yml

@@ -217,13 +217,14 @@ jobs:
           brew install pkg-config
       - name: Build wheels
         env:
+          CIBW_ARCHS_WINDOWS: AMD64
           CIBW_BEFORE_BUILD: pip install cython && python scripts/fetch-vendor /tmp/vendor
           CIBW_BEFORE_BUILD_WINDOWS: pip install cython && python scripts\fetch-vendor C:\cibw\vendor
           CIBW_ENVIRONMENT_LINUX: LD_LIBRARY_PATH=/tmp/vendor/lib:$LD_LIBRARY_PATH PKG_CONFIG_PATH=/tmp/vendor/lib/pkgconfig
           CIBW_ENVIRONMENT_MACOS: PKG_CONFIG_PATH=/tmp/vendor/lib/pkgconfig LDFLAGS=-headerpad_max_install_names
           CIBW_ENVIRONMENT_WINDOWS: INCLUDE=C:\\cibw\\vendor\\include LIB=C:\\cibw\\vendor\\lib PYAV_SKIP_TESTS=unicode_filename
           CIBW_REPAIR_WHEEL_COMMAND_WINDOWS: python scripts/inject-dll {wheel} {dest_dir} C:\cibw\vendor\bin
-          CIBW_SKIP: cp27-* pp27-* pp36-win*
+          CIBW_SKIP: cp36-* pp36-* *-musllinux*
           CIBW_TEST_COMMAND: mv {project}/av {project}/av.disabled && python -m unittest discover -t {project} -s tests && mv {project}/av.disabled {project}/av
           # disable test suite on OS X, the SSL config seems broken
           CIBW_TEST_COMMAND_MACOS: true

scripts/fetch-vendor.json

@@ -1,3 +1,3 @@
 {
-    "urls": ["https://github.com/PyAV-Org/pyav-ffmpeg/releases/download/4.3.1-1/ffmpeg-{platform}.tar.gz"]
+    "urls": ["https://github.com/PyAV-Org/pyav-ffmpeg/releases/download/4.3.2-1/ffmpeg-{platform}.tar.gz"]
 }

setup.py

@@ -526,11 +526,11 @@ def run(self):
        'Operating System :: Unix',
        'Operating System :: Microsoft :: Windows',
        'Programming Language :: Cython',
-       'Programming Language :: Python :: 3.5',
        'Programming Language :: Python :: 3.6',
        'Programming Language :: Python :: 3.7',
        'Programming Language :: Python :: 3.8',
        'Programming Language :: Python :: 3.9',
+       'Programming Language :: Python :: 3.10',
        'Topic :: Software Development :: Libraries :: Python Modules',
        'Topic :: Multimedia :: Sound/Audio',
        'Topic :: Multimedia :: Sound/Audio :: Conversion',