Version bump in docs

Author: dahlia

docs/frameworks/flask.rst

@@ -135,7 +135,7 @@ Add these arguments to :file:`setup.py` script::
 
     setup(
         # ...,
-        setup_requires=['libsass >= 0.2.0'],
+        setup_requires=['libsass >= 0.6.0'],
         sass_manifests={
             'myapp': ('static/sass', 'static/css', '/static/css')
         }

sassutils/distutils.py

@@ -12,7 +12,7 @@
 
     setup(
         # ...,
-        setup_requires=['libsass >= 0.2.0']
+        setup_requires=['libsass >= 0.6.0']
     )
 
 It will adds :class:`build_sass` command to the :file:`setup.py` script:
@@ -37,7 +37,7 @@
         sass_manifests={
             'your.webapp': ('static/sass', 'static/css')
         },
-        setup_requires=['libsass >= 0.2.0']
+        setup_requires=['libsass >= 0.6.0']
     )
 
 The option should be a mapping of package names to pairs of paths, e.g.::