Merge pull request buildkite#1816 from buildkite/upgrade-agent-v.3.42.0

Author: mitchbne

pages/agent/v3/help/_bootstrap.md

@@ -64,6 +64,7 @@ See https://buildkite.com/docs/agent/v3/hooks for more details.
 <tr id="git-clone-mirror-flags"><th><code>--git-clone-mirror-flags value</code> <a class="Docs__attribute__link" href="#git-clone-mirror-flags">#</a></th><td><p>Flags to pass to "git clone" command when mirroring (default: "-v")<br /><strong>Environment variable</strong>: <code>$BUILDKITE_GIT_CLONE_MIRROR_FLAGS</code></p></td></tr>
 <tr id="git-clean-flags"><th><code>--git-clean-flags value</code> <a class="Docs__attribute__link" href="#git-clean-flags">#</a></th><td><p>Flags to pass to "git clean" command (default: "-ffxdq")<br /><strong>Environment variable</strong>: <code>$BUILDKITE_GIT_CLEAN_FLAGS</code></p></td></tr>
 <tr id="git-fetch-flags"><th><code>--git-fetch-flags value</code> <a class="Docs__attribute__link" href="#git-fetch-flags">#</a></th><td><p>Flags to pass to "git fetch" command<br /><strong>Environment variable</strong>: <code>$BUILDKITE_GIT_FETCH_FLAGS</code></p></td></tr>
+<tr id="git-submodule-clone-config"><th><code>--git-submodule-clone-config value</code> <a class="Docs__attribute__link" href="#git-submodule-clone-config">#</a></th><td><p>Comma separated key=value git config pairs applied before git submodule clone commands, e.g. `update --init`. If the config is needed to be applied to all git commands, supply it in a global git config file for the system that the agent runs in instead.<br /><strong>Environment variable</strong>: <code>$BUILDKITE_GIT_SUBMODULE_CLONE_CONFIG</code></p></td></tr>
 <tr id="git-mirrors-path"><th><code>--git-mirrors-path value</code> <a class="Docs__attribute__link" href="#git-mirrors-path">#</a></th><td><p>Path to where mirrors of git repositories are stored<br /><strong>Environment variable</strong>: <code>$BUILDKITE_GIT_MIRRORS_PATH</code></p></td></tr>
 <tr id="git-mirrors-lock-timeout"><th><code>--git-mirrors-lock-timeout value</code> <a class="Docs__attribute__link" href="#git-mirrors-lock-timeout">#</a></th><td><p>Seconds to lock a git mirror during clone, should exceed your longest checkout (default: 300)<br /><strong>Environment variable</strong>: <code>$BUILDKITE_GIT_MIRRORS_LOCK_TIMEOUT</code></p></td></tr>
 <tr id="git-mirrors-skip-update"><th><code>--git-mirrors-skip-update </code> <a class="Docs__attribute__link" href="#git-mirrors-skip-update">#</a></th><td><p>Skip updating the Git mirror<br /><strong>Environment variable</strong>: <code>$BUILDKITE_GIT_MIRRORS_SKIP_UPDATE</code></p></td></tr>