INSTALLING.md: update Linux distribution examples

As announced with the v3.6.0 release of the Git LFS client, and as
noted in commit 23fbfe8 of PR git-lfs#5911,
since all the distribution versions based on Red Hat Enterprise Linux
(RHEL) 7, CentOS 7, and SUSE Linux Enterprise Server (SLES) 12 for which
we previously built RPM packages have now reached the end of their
standard LTS (Long-Term Support) periods, future releases of Git LFS
will no longer provide support for these platforms or build packages
for them.

Because we anticipate making a v3.7.0 release of the Git LFS client in
the near future, we removed the Dockerfile we used to build packages
for the RHEL/CentOS 7 and SLES 12 platforms in commit
git-lfs/build-dockers@cfde130 of
PR git-lfs/build-dockers#71.  We then also removed the entries for
these platforms from the list of our supported Linux distribution
versions in the DistroMap Ruby class source file, which is utilized
by several scripts run by our GitHub Actions release workflow jobs
when building and naming the Linux packages we publish on Packagecloud.

Previously, in commit ff36182 of
PR git-lfs#4328, we removed support for distribution versions based on the
Debian 8 ("jessie") platform, including Ubuntu 14.04 ("Trusty Tahr")
and Linux Mint 17.1 ("Rebecca").

However, some of the installation examples in our "INSTALLING.md"
page still reference these platforms, so we update these exmaples
now with more contemporary Linux distribution versions.

Author: chrisd8088

INSTALLING.md

@@ -9,7 +9,7 @@ packagecloud provides scripts to automate the process of configuring the package
 * apt/deb repositories: https://packagecloud.io/install/repositories/github/git-lfs/script.deb.sh
 * yum/rpm repositories: https://packagecloud.io/install/repositories/github/git-lfs/script.rpm.sh
 
-The scripts check your Linux distribution and version, and use those parameters to create the best repository URL.  If you are running one of the distributions listed for the latest version of Git LFS listed at [packagecloud](https://packagecloud.io/github/git-lfs) e.g `debian/jessie`, `el/7`, you can run the script without parameters:
+The scripts check your Linux distribution and version, and use those parameters to create the best repository URL.  If you are running one of the distributions listed for the latest version of Git LFS listed at [packagecloud](https://packagecloud.io/github/git-lfs) e.g., `debian/bookworm`, `el/9`, you can run the script without parameters:
 
 apt/deb repos:
 `curl -s https://packagecloud.io/install/repositories/github/git-lfs/script.deb.sh | sudo bash`
@@ -19,9 +19,9 @@ yum/rpm repos:
 
 If you are running a distribution which does not match exactly a repository uploaded for Git LFS, but for which there is a repository for a compatible upstream distribution, you can either run the script with some additional parameters, or run it and then manually-correct the resulting repository URLs.  See [#1074](https://github.com/git-lfs/git-lfs/issues/1074) for details.
 
-If you are running LinuxMint 17.1 Rebecca, which is downstream of Ubuntu Trusty and Debian Jessie, you can run:
+If you are running Linux Mint 22.1 Xia, which is downstream of Ubuntu Noble and Debian Bookworm, you can run:
 
-`curl -s https://packagecloud.io/install/repositories/github/git-lfs/script.deb.sh | os=debian dist=jessie sudo -E bash`
+`curl -s https://packagecloud.io/install/repositories/github/git-lfs/script.deb.sh | os=debian dist=xia sudo -E bash`
 
 The `os` and `dist` variables passed-in will override what would be detected for your system and force the selection of the upstream distribution's repository.