Fix spelling of Python 3.5-specific requirements

According to PEP 440, `~="3.5"` is equivalent to `>="3.5", =="3.*"` -
that is, any 3.x version from 3.5 on.  I don't think that's what was
intended in most of these cases, and the effect is that resolvers on
recent versions of Python end up pinning to the versions that work on
3.5, which is pretty excessive.

In most of these cases, `~="3.5.0"` is a better spelling, restricting
these pins to Python 3.5.x.  The exceptions seem to be `aiocontextvars`
and `contextvars`, which were needed in Python 3.5 and 3.6, but aren't
needed as of 3.7 since `contextvars` is in the standard library there; I
think `>="3.5"` plus `<"3.7"` and similar makes more sense for those
cases.  (Comments in `talisker.context` indicate that `aiocontextvars`
specifically requires at least 3.5.3.)

setup.cfg

@@ -42,31 +42,31 @@ packages = talisker
 test_suite = tests
 package_dir = talisker=talisker
 install_requires =
-	Werkzeug~=1.0;python_version~="3.5"
+	Werkzeug~=1.0;python_version~="3.5.0"
 	Werkzeug<3;python_version>"3.6"
-	statsd~=3.3;python_version~="3.5"
+	statsd~=3.3;python_version~="3.5.0"
 	statsd<4;python_version>"3.6"
-	requests~=2.25;python_version~="3.5"
+	requests~=2.25;python_version~="3.5.0"
 	requests<3.0;python_version>"3.5"
 	future~=0.18
-	contextvars~=2.4;python_version~="3.5"
+	contextvars~=2.4;python_version>="3.5" and python_version<"3.7"
 
 [options.extras_require]
 gunicorn = gunicorn>=19.7.0
 raven = raven>=6.4.0
 celery =
-	celery~=4.4;python_version~="3.5"
+	celery~=4.4;python_version~="3.5.0"
 	celery>=4,<5.3;python_version>"3.5"
 django =
-    django~=2.2;python_version~="3.5"
+	django~=2.2;python_version~="3.5.0"
 	django<4;python_version>"3.5"
 prometheus =
-	prometheus-client~=0.7.0;python_version~="3.5"
+	prometheus-client~=0.7.0;python_version~="3.5.0"
 	prometheus-client<0.8;python_version>"3.5"
 flask =
-	flask~=1.1;python_version~="3.5"
+	flask~=1.1;python_version~="3.5.0"
 	flask<3;python_version>"3.5"
-	blinker~=1.5;python_version~="3.5"
+	blinker~=1.5;python_version~="3.5.0"
 	blinker<2;python_version>"3.5"
 dev =
 	logging_tree>=1.9
@@ -77,7 +77,7 @@ pg =
 	sqlparse>=0.4.2
 	psycopg2>=2.8,<3.0
 asyncio =
-	aiocontextvars==0.2.2;python_version~="3.5"
+	aiocontextvars==0.2.2;python_version>="3.5.3" and python_version<"3.7"
 gevent = gevent>=20.9.0
 
 [options.package_data]

setup.py

@@ -142,10 +142,10 @@
     ),
     extras_require=dict(
         asyncio=[
-            'aiocontextvars==0.2.2;python_version~="3.5"',
+            'aiocontextvars==0.2.2;python_version>="3.5.3" and python_version<"3.7"',
         ],
         celery=[
-            'celery~=4.4;python_version~="3.5"',
+            'celery~=4.4;python_version~="3.5.0"',
             'celery>=4,<5.3;python_version>"3.5"',
         ],
         dev=[
@@ -155,13 +155,13 @@
             'objgraph>=3.5',
         ],
         django=[
-            'django~=2.2;python_version~="3.5"',
+            'django~=2.2;python_version~="3.5.0"',
             'django<4;python_version>"3.5"',
         ],
         flask=[
-            'flask~=1.1;python_version~="3.5"',
+            'flask~=1.1;python_version~="3.5.0"',
             'flask<3;python_version>"3.5"',
-            'blinker~=1.5;python_version~="3.5"',
+            'blinker~=1.5;python_version~="3.5.0"',
             'blinker<2;python_version>"3.5"',
         ],
         gevent=[
@@ -175,7 +175,7 @@
             'psycopg2>=2.8,<3.0',
         ],
         prometheus=[
-            'prometheus-client~=0.7.0;python_version~="3.5"',
+            'prometheus-client~=0.7.0;python_version~="3.5.0"',
             'prometheus-client<0.8;python_version>"3.5"',
         ],
         raven=[
@@ -184,14 +184,14 @@
     ),
     include_package_data=True,
     install_requires=[
-        'Werkzeug~=1.0;python_version~="3.5"',
+        'Werkzeug~=1.0;python_version~="3.5.0"',
         'Werkzeug<3;python_version>"3.6"',
-        'statsd~=3.3;python_version~="3.5"',
+        'statsd~=3.3;python_version~="3.5.0"',
         'statsd<4;python_version>"3.6"',
-        'requests~=2.25;python_version~="3.5"',
+        'requests~=2.25;python_version~="3.5.0"',
         'requests<3.0;python_version>"3.5"',
         'future~=0.18',
-        'contextvars~=2.4;python_version~="3.5"',
+        'contextvars~=2.4;python_version>="3.5" and python_version<"3.7"',
     ],
     keywords=[
         'talisker',