Bump haml from 4.0.7 to 5.1.2

Bumps [haml](https://github.com/haml/haml) from 4.0.7 to 5.1.2.
- [Release notes](https://github.com/haml/haml/releases)
- [Changelog](https://github.com/haml/haml/blob/master/CHANGELOG.md)
- [Commits](haml/haml@4.0.7...v5.1.2)

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -31,14 +31,16 @@ GEM
     fastimage (1.8.1)
       addressable (~> 2.3, >= 2.3.5)
     ffi (1.9.10)
-    haml (4.0.7)
+    haml (5.1.2)
+      temple (>= 0.8.0)
       tilt
     hamster (2.0.0)
       concurrent-ruby (~> 0.8)
     hashie (3.4.3)
     i18n (0.7.0)
     json (1.8.5)
     kramdown (1.9.0)
+    libv8 (3.16.14.19)
     listen (3.0.5)
       rb-fsevent (>= 0.9.3)
       rb-inotify (>= 0.9)
@@ -103,10 +105,15 @@ GEM
     rb-inotify (0.9.5)
       ffi (>= 0.5.0)
     redcarpet (3.3.4)
+    ref (2.0.0)
     rouge (1.10.1)
     sass (3.4.21)
     sprockets (3.4.1)
       rack (> 1, < 3)
+    temple (0.8.2)
+    therubyracer (0.12.3)
+      libv8 (~> 3.16.14.15)
+      ref
     thor (0.19.1)
     thread_safe (0.3.5)
     tilt (1.4.1)
@@ -129,6 +136,7 @@ DEPENDENCIES
   middleman-syntax (~> 2.1.0)
   redcarpet (~> 3.3.2)
   rouge (~> 1.10.1)
+  therubyracer
 
 BUNDLED WITH
    1.10.6