Changelog (v7.1.0-RC1...v7.1.0)

• bug [DoctrineBridge] Revert deprecating by-{id} mapping of entities #57248 [DoctrineBridge] Revert deprecating by-{id} mapping of entities (@nicolas-grekas)
• bug [Mailer] Fix sendmail transport failure handling and interactive mode #54572 [Mailer] Fix sendmail transport failure handling and interactive mode (@bobvandevijver)
• bug [Mime] fix PHP 7 compatibility #57228 [Mime] fix PHP 7 compatibility (@xabbuh)
• bug [Mime] Fixed Mime\Message::ensureValidity() when a required header is set, but has an empty body #57065 [Mime] Fixed Mime\Message::ensureValidity() when a required header is set, but has an empty body (@rhertogh)
• bug [Config] gracefully handle cases when no resolver is set #57069 [Config] gracefully handle cases when no resolver is set (@xabbuh)
• bug [Notifier] keep boolean options when their value is false #57109 [Notifier] keep boolean options when their value is false (@xabbuh)
• bug [DoctrineBridge] Undeprecate DoctrineExtractor::getTypes() #56848 [DoctrineBridge] Undeprecate DoctrineExtractor::getTypes() (@derrabus)
• bug [Serializer] Cache readability/writability computation #54971 [Serializer] Cache readability/writability computation (@mtarld)
• bug [Cache] Fix irrelevant deprecation when connecting to Couchbase #54979 [Cache] Fix irrelevant deprecation when connecting to Couchbase (@derrabus)
• bug Fix CharsetValidator with string encoding #56827 Fix CharsetValidator with string encoding (@alamirault)
• bug [DependencyInjection] Fix prepending strategy for php config loader #54977 [DependencyInjection] Fix prepending strategy for php config loader (@yceruto)
• bug [VarExporter] Fix exporting default values involving global constants #56488 [VarExporter] Fix exporting default values involving global constants (@kylekatarnls)