Remove support of Python 3.7

Python 3.7 reached its end of life in June 2023 and it is not even
supported by some of the GH actions.

.github/workflows/main.yml

@@ -6,7 +6,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: [3.7, 3.8, 3.9, '3.10', '3.11', '3.12', 'pypy-3.9']
+        python-version: [3.8, 3.9, '3.10', '3.11', '3.12', 'pypy-3.9']
         exclude:
           # NOTE: pynacl should not be built from sdist, but it has no binary
           # wheel available for windows+pypy

README.rst

@@ -56,7 +56,7 @@ interfaces:
 Requirements
 ============
 
-* Python_ >= 3.7
+* Python_ >= 3.8
 * MongoDB_ >= 3.6 (either local installation or access to remote database)
 * Java_ SE >= 7 JRE or JDK (optional, required if the *Picireny* test case
   reducer is used)

setup.cfg

@@ -14,7 +14,6 @@ classifiers =
     # Operating System :: OS Independent
     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
@@ -27,11 +26,10 @@ package_dir =
     = src
 packages = find:
 include_package_data = True
-python_requires = >=3.7
+python_requires = >=3.8
 install_requires =
     chevron
     google-api-python-client
-    importlib-metadata; python_version < "3.8"
     inators
     jinja2
     keyring