VERSION: release v0.3.6

[cyphar]

github.com/cyphar/filepath-securejoin v0.3.6

This release lowers the minimum Go version to Go 1.18 as well as some
library dependencies, in order to make it easier for folks that need to
backport patches using the new filepath-securejoin API onto branches
that are stuck using old Go compilers. For users using Go >= 1.21, this
release contains no functional changes.

* The minimum Go version requirement for filepath-securejoin is now Go 1.18
  (we use generics internally).

  For reference, [email protected] somewhat-arbitrarily bumped the
  Go version requirement to 1.21.

  While we did make some use of Go 1.21 stdlib features (and in principle Go
  versions <= 1.21 are no longer even supported by upstream anymore), some
  downstreams have complained that the version bump has meant that they have to
  do workarounds when backporting fixes that use the new filepath-securejoin
  API onto old branches. This is not an ideal situation, but since using this
  library is probably better for most downstreams than a hand-rolled
  workaround, we now have compatibility shims that allow us to build on older
  Go versions.

* Lower minimum version requirement for golang.org/x/sys to v0.18.0 (we
  need the wrappers for fsconfig(2)), which should also make backporting
  patches to older branches easier.

Signed-off-by: Aleksa Sarai <[email protected]>