Release 7.3.1

[daghf]

Reviewers must check the following items:

• Release notes are complete (major release only)
• Release notes no longer target trunk (major release only)
• The change log is populated
• The VRT history in include/vrt.h is populated
• The VRT history refers to the next VRT version
• The macro VRT_MAJOR_VERSION was updated if applicable
• The macro VRT_MINOR_VERSION was updated if applicable
• The new VRT version follows releases guidelines
• The new VRT version matches the one from the VRT history
• Bundled devicedetect.vcl was updated (major release only)
• Running ./autogen.des && make distcheck succeeds
• The version in configure.ac is correct
• The copyright notice in configure.ac covers the current year
• The copyright output in lib/libvarnish/version.c covers the current year
• There are no other changes than the ones listed above

[dridi]

Waiting for CI, and also distcheck to complete on my machine.

[dridi]

Tests are failing in CI due to a lack of resources. One test is failing for the deprecated persistent storage, which will not block the release.