[MISC] (deps): Bump just-the-docs from 0.2.7 to 0.2.9 in /docs (#1151)

Bumps [just-the-docs](https://github.com/pmarsceill/just-the-docs) from 0.2.7 to 0.2.9.
- [Release notes](https://github.com/pmarsceill/just-the-docs/releases)
- [Commits](https://github.com/pmarsceill/just-the-docs/compare/v0.2.7...v0.2.9)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

docs/Gemfile.lock

@@ -28,7 +28,7 @@ GEM
     execjs (2.7.0)
     faraday (1.0.1)
       multipart-post (>= 1.2, < 3)
-    ffi (1.12.2)
+    ffi (1.13.1)
     forwardable-extended (2.6.0)
     gemoji (3.0.1)
     github-pages (206)
@@ -191,10 +191,10 @@ GEM
       gemoji (~> 3.0)
       html-pipeline (~> 2.2)
       jekyll (>= 3.0, < 5.0)
-    just-the-docs (0.2.7)
-      jekyll (~> 3.8.5)
+    just-the-docs (0.2.9)
+      jekyll (>= 3.8.5, < 4.1.0)
       jekyll-seo-tag (~> 2.0)
-      rake (~> 12.3.1)
+      rake (>= 12.3.1, < 13.1.0)
     kramdown (1.17.0)
     liquid (4.0.3)
     listen (3.2.1)
@@ -216,7 +216,7 @@ GEM
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (3.1.1)
-    rake (12.3.3)
+    rake (13.0.1)
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)