* Fix build with OpenSSL 3.0
- FIPS_mode_set() does not exist in OpenSSL 3.0 [1]
- X509_check_* functions declarated in openssl/x509v3.h instead of openssl/x509.h [2]
- X509_chack_* functions have const char arg inserad of const unsigned char [2]
- skip MD4 tests if it is unsupported by OpenSSL
- the patch does not change behavior under OpenSSL version != 3
- the patch just fixes build under OpenSSL 3.0 and doesn't update deprecated code
or behavior
1. https://wiki.openssl.org/index.php/OpenSSL_3.0#Upgrading_from_the_OpenSSL_2.0_FIPS_Object_Module
2. https://www.openssl.org/docs/man3.0/man3/X509_check_host.html
* Add Ubuntu 22.04 runner to GitHub Actions go test workflow
* Fix flaky tests on Ubuntu 22.04
It is necessary to handle OpenSSL errors very carefully. Otherwise,
errors may appear in unexpected places. For example, we didn't catch
an error from EVP_DigestInit_ex() and it appears sometimes in conn.go:
func (c *Conn) getErrorHandler(rv C.int, errno error) func() error {
errcode := C.SSL_get_error(c.ssl, rv) // <- here
