Allow modern Cryptography

• Fix compatibility with Cryptography 35
• Use default httpc timeout if unset
• Test on Python 3.10
• Update test vectors to work with Cryptography 35

What's Changed

• deprecate alg=RSA1_5 by @jschlyter in #86
• fix: RSA1_5 replaced by RSA-OAEP in doc examples by @peppelinux in #89
• add Python 3.10 rc by @jschlyter in #87
• build with 3.10 release by @jschlyter in #92
• default httpc timeout if unset by @peppelinux in #94
• feat: httpc_params_loader (httpc default timeout refactor) by @peppelinux in #95
• To be able to verify that keys are of a certain length/size. by @rohe in #96
• X509 test vector by @rohe in #99
• Upgrade to Cryptography 35 by @jschlyter in #98
• prepare for release v1.6.0 by @jschlyter in #100

Full Changelog: 1.5.2...1.6.0