remove Python 3.6 only deps

Author: mr-c

README.rst

@@ -23,7 +23,7 @@ generation, and transformation to RDF_. Salad provides a bridge
 between document and record oriented data modeling and the Semantic
 Web.
 
-The Schema Salad library is Python 3.6+ only.
+The Schema Salad library is Python 3.7+ only.
 
 Installation
 ------------

mypy-requirements.txt

@@ -2,4 +2,3 @@ mypy==0.931
 black>=19.10b0
 types-pkg_resources
 types-requests
-types-dataclasses;python_version < "3.7"

requirements.txt

@@ -1,7 +1,5 @@
 ruamel.yaml>= 0.12.4, != 0.16.6, < 0.18
-rdflib>= 4.2.2, < 6.0.0;python_version<='3.6'
 rdflib>= 4.2.2, < 7.0.0
-rdflib-jsonld>=0.4.0, <= 0.6.1;python_version<='3.6'
 mistune>=0.8.1,<0.9
 CacheControl==0.12.10
 lockfile==0.12.2  # needed for CacheControl's FileCache

setup.py

@@ -77,9 +77,7 @@
     "ruamel.yaml >= 0.12.4, != 0.16.6, < 0.18",
     # once the minimum version for ruamel.yaml >= 0.15.99
     # then please update the mypy targets in the Makefile
-    "rdflib >= 4.2.2, < 6.0.0;python_version<='3.6'",
     "rdflib >= 4.2.2, < 7.0.0",
-    "rdflib-jsonld >= 0.3.0, <= 0.6.1;python_version<='3.6'",
     "mistune >= 0.8.1, < 0.9",
     "CacheControl >= 0.11.7, < 0.13",
     "lockfile >= 0.9",  # needed for CacheControl's FileCache