Update heat-translator-1.3.1 for param values

If user provides parameter file while creating VNF using scaling policy,
earlier it was failing with error 'The Parameter was not provided". This issue
already fixed in heat-translator-1.3.1.
Update lower-constraints.txt and requirements.txt with the same.

Depends-On: I67b9f53ac4cc0e4318fb7d62ac3d389c8cafbab2o
Change-Id: Ie1a6d859f91d8ad2decaaa1606dda1858df782a0
Closes-Bug: #1823860
Closes-Bug: #1799683

lower-constraints.txt

@@ -36,7 +36,7 @@ futurist==1.6.0
 google-auth==1.4.1
 greenlet==0.4.13
 hacking==0.12.0
-heat-translator==1.3.0
+heat-translator==1.3.1
 idna==2.6
 imagesize==1.0.0
 ipaddress==1.0.19

requirements.txt

@@ -39,7 +39,7 @@ openstackdocstheme>=1.18.1 # Apache-2.0
 python-neutronclient>=6.7.0 # Apache-2.0
 python-novaclient>=9.1.0 # Apache-2.0
 tosca-parser>=0.8.1 # Apache-2.0
-heat-translator>=1.3.0 # Apache-2.0
+heat-translator>=1.3.1 # Apache-2.0
 cryptography>=2.1 # BSD/Apache-2.0
 paramiko>=2.0.0 # LGPLv2.1+
 pyroute2>=0.4.21;sys_platform!='win32' # Apache-2.0 (+ dual licensed GPL2)