Release 2023.2

NOTE: As usual, some of these commits are actually for the Rust bindings,
which are versioned and released separately.

Though speaking of bindings in general,
there's a lot of cleanup that landed to the annotations around
nullability in general, which should improve ergonomics.  These
changes will be reflected in a future release of the Rust bindings
specifically too.

Otherwise, we have some small tweaks and improvements in various places,
from a performance improvement in commits to test suite fixes.

A notable thing that landed here is fixes for recent GLibs introducing
warnings around unset `standard::size`.

Thanks to all contributors!

```
Colin Walters (18):
      Add `sysroot.bootprefix` option
      deploy: Use `semodule --refresh` if available
      configure: post-release version bump
      Release rust/ bindings 0.17.1
      rust-bindings: Regenerate for 2023.1
      rust-bindings: `Sysroot` is `Send`
      itest-pull-space: Use mkfs.ext4, align to at least 512b
      tests: Set size on fileinfo
      Enable `trust_return_value_nullability`
      Add docs and fix annotations for ostree-repo-file.c
      rust: Bump semver
      lib: Fix two nullable annotations
      repo: Fix nullability for remote options
      rust: Renerate bindings
      Revert "repo: Fix nullability for remote options"
      rust-bindings: Regenerate
      Release 2023.2
      configure: post-release version bump

Corentin Noël (3):
      build: Do not include private headers in the introspection
      libostree: Ignore new_and_connect in the introspection
      libostree: Enhance the annotation coverage

Evan Anderson (1):
      core: Ensure glib standard::size attribute is always set

Jonathan Lebon (1):
      ci: update for new kolaTestIso()

Philip Withnall (1):
      lib/fetcher-util: Wake up main context when a request is complete

Seppo Yli-Olli (1):
      Increase buffer size for create_regular_tmpfile_linkable_with_content

Simon McVittie (5):
      tests: Ensure non-root users have access to libcap tools
      ostree_raw_file_to_content_stream: Make size default to 0
      _ostree_zlib_file_header_new: Default size to 0
      write_content_object: Don't assume file info has standard::size
      Use g_steal_fd() in preference to glnx_steal_fd()

Timothée Ravier (1):
      docs: Use upstream theme & update to 0.4.1

dependabot[bot] (1):
      build(deps): bump libglnx from `4e44fd9` to `07e3e49`
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