Revert "build(deps): bump regex from 1.10.6 to 1.11.0"

[cgwalters]

This reverts commit c46951f.

I get a conflict now, this appears to be a case of independent PRs working together but conflicting after merge.

$ cargo check
error: failed to select a version for `regex`.
    ... required by package `oci-spec v0.7.0`
    ... which satisfies dependency `oci-spec = "^0.7.0"` (locked to 0.7.0) of package `containers-image-proxy v0.7.0`
    ... which satisfies dependency `containers-image-proxy = "^0.7.0"` (locked to 0.7.0) of package `ostree-ext v0.15.2`
    ... which satisfies dependency `ostree-ext = "^0.15"` (locked to 0.15.2) of package `rpmostree-rust v0.1.0 (/var/home/walters/src/github/coreos/rpm-ostree)`
versions that meet the requirements `~1.10.5` are: 1.10.6, 1.10.5

all possible versions conflict with previously selected packages.

  previously selected package `regex v1.11.0`
    ... which satisfies dependency `regex = "^1.11"` (locked to 1.11.0) of package `rpmostree-rust v0.1.0 (/var/home/walters/src/github/coreos/rpm-ostree)`

failed to select a version for `regex` which could resolve this conflict