Release and vulnerability announcements for strongSwan

We are happy to announce the release of strongSwan 5.7.0, which brings support for SWIMA for PA-TNC, swanctl.conf/strongswan.conf syntax changes, a Botan crypto library plugin, support for Postquantum Preshared Keys for IKEv2, fixes a potential authorization bypass vulnerability, and comes with several other new features and fixes.