pycares-3.1.0

• misc: add Python 3.8 classifier
• (origin/master, origin/HEAD) build: use Travis to build Python Wheels
• ci: use GH Actions to test on macOS
• ci: run tests in Python 3.8 too
• test: remove no longer valid test
• test: remove empty test
• errno: return str from errno.strerror
• core: fix crash when processing .onion queries
• test: fix test_query_txt_multiple_chunked
• doc: fix path of _version.py file
• core: fix support for ARES_OPT_LOOKUPS option
• build: add cygwin support
• core: fix struct in6_addr alignment
• misc: simplify non-ascii txt test example
• core: fix long TXT record with non-ascii bytes
• build: remove extra add_include_dir line on linux
• build: fix testing manylinux wheels