Import current master (2c43241dc0ed) of ruby/openssl.git.

Below are the commits that were made since the last batch at commit
b99775b1 (ruby/openssl.git commit f49e7110ca1e). Note that some of
them have been applied already.

----------------------------------------------------------------
Benoit Daloze (1):
      Remove redundant and ignored workflow file

DBL-Lee (1):
      add support for SHA512_256/SHA512_224

Hiroshi SHIBATA (2):
      Guard for OpenSSL::PKey::EC::Group::Error with unsupported platforms
      Fixed inconsistency directory structure with ruby/ruby repo

Jeremy Evans (2):
      Fix keyword argument separation issues in OpenSSL::SSL::SSLSocket#sys{read,write}_nonblock
      Remove taint support

Kazuki Yamaguchi (26):
      config: support .include directive
      random: make OpenSSL::Random.pseudo_bytes alias of .random_bytes
      extconf.rb: get rid of -Werror=deprecated-declarations
      test/openssl/test_ssl: skip test_fallback_scsv if necessary
      ts: simplify OpenSSL::Timestamp::Request#algorithm
      History.md: add missing references to GitHub issues
      config: deprecate OpenSSL::Config#add_value and #[]=
      test/openssl/test_ssl: remove sleep from test_finished_messages
      test/openssl/test_ssl: fix random failure in SSLSocket.open test
      test/openssl/test_ssl: avoid explicitly-sized private keys
      test/openssl/test_ssl: remove commented-out test case
      test/openssl/test_ssl: allow kRSA tests to fail
      ssl: avoid declarations after statements
      engine: revert OpenSSL::Engine.load changes for cloudhsm
      engine: remove really outdated static engines
      engine: do not check for ENGINE_load_builtin_engines()
      engine: fix guards for 'dynamic' and 'cryptodev' engines
      lib/openssl.rb: require openssl/version.rb
      x509: add error code and verify flags constants
      ssl: set verify error code in the case of verify_hostname failure
      .github/workflows: merge CI jobs into a single workflow
      .github/workflows: test against different OpenSSL versions
      .travis.yml: fully migrate to GitHub Actions
      ssl: suppress test failure with SSLContext#add_certificate_chain_file
      ssl: remove test case test_puts_meta from test_pair
      Revert "Use version.rb in gemspec"

MSP-Greg (2):
      .travis.yml - remove 2.3/1.0.2, 2.5/1.1.1, head/1.0.2
      Use version.rb in gemspec

Samuel Williams (1):
      Restore compatibility with older versions of Ruby.

Yusuke Endoh (1):
      Make OpenSSL::OSSL#test_memcmp_timing robust