Update git submodules

* Update docs/submodules/modeling/modelspec.git from branch 'master'
  to 7df1c0320f8888992f18882e96ba3cb26ff7b32c
  - Update css file name in conf.py
    
    ribbon.css is the correct name of the css file.
    
    Issue-ID: CIMAN-376
    Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
    Change-Id: I73abfcf735b19995b9d9e95dcc60e407b8f36945
    
diff --git a/docs/submodules/modeling/modelspec.git b/docs/submodules/modeling/modelspec.git
index e9d4fc1..7df1c03 160000
--- a/docs/submodules/modeling/modelspec.git
+++ b/docs/submodules/modeling/modelspec.git
@@ -1 +1 @@
-Subproject commit e9d4fc1e6ea5f43811d068db48c3f6847cf0dd66
+Subproject commit 7df1c0320f8888992f18882e96ba3cb26ff7b32c