Fixed a RST syntax issue

javiereguiluz · javiereguiluz · commit c90f20a94e2e · 2018-06-29T18:00:25.000+02:00
diff --git a/frontend/encore/bootstrap.rst b/frontend/encore/bootstrap.rst
@@ -1,5 +1,5 @@
 Using Bootstrap CSS & JS
-============================
+========================
 
 Want to use Bootstrap (or something similar) in your project? No problem!
 First, install it. To be able to customize things further, we'll install
