Drop support for Python 3.7

We haven't tested this in the gate for some time and it's been known
broken.

Change-Id: Ied4f04189447330ec664d2c2dbc21a6ac6ef4f6c
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

setup.cfg

@@ -6,7 +6,7 @@ description_file =
 author = OpenStack
 author_email = openstack-discuss@lists.openstack.org
 home_page = https://docs.openstack.org/openstacksdk/
-python_requires = >=3.7
+python_requires = >=3.8
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -15,7 +15,6 @@ classifier =
     Operating System :: POSIX :: Linux
     Programming Language :: Python
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10

tox.ini

@@ -23,7 +23,7 @@ commands =
     stestr run {posargs}
     stestr slowest
 
-[testenv:functional{,-py37,-py38,-py39,-py310,-py311,-py312}]
+[testenv:functional{,-py38,-py39,-py310,-py311,-py312}]
 description =
     Run functional tests.
 # Some jobs (especially heat) takes longer, therefore increase default timeout