Formalise support for Python 3.10

This includes adding tests on Travis, and adding the classifier in the
package description.

Signed-off-by: Rodrigo Tobar <rtobar@icrar.org>

.travis.yml

@@ -83,7 +83,8 @@ jobs:
     - python: "3.7"
       env: YAJL_VERSION=none
     - python: "3.8"
-    - python: "3.9-dev"
+    - python: "3.9"
+    - python: "3.10-dev"
 
     #build wheels
     - name: linux wheels build

CHANGELOG.md

@@ -7,6 +7,7 @@
   This tool should be useful for new users
   who are usually confused with how to use the library,
   and the prefix in particular.
+* Mark Python 3.10 as explicitly supported.
 
 ## [3.1.4]
 

setup.py

@@ -37,6 +37,7 @@ def get_ijson_version():
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
+        'Programming Language :: Python :: 3.10',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Software Development :: Libraries :: Python Modules',