Drop support for Python 3.7.

Python 3.7 reaches end-of-life on 27 June 2023 (https://devguide.python.org/versions/), and future versions of MuJoCo (after 2.3.6) will no longer support it.

PiperOrigin-RevId: 543594006
Change-Id: Ia65cde4e2d0dcf092319083d314ae53518922c12

requirements.txt

@@ -2,23 +2,20 @@ absl-py==1.4.0
 dm-env==1.6
 dm-tree==0.1.8
 glfw==1.12.0
-h5py==3.8.0; python_version == '3.7'
-h5py==3.9.0; python_version >= '3.8'
+h5py==3.9.0
 labmaze==1.0.6
 lxml==4.9.2
 mock==5.0.2
 mujoco==2.3.6
 nose==1.3.7
 nose-xunitmp==0.4.1
-numpy==1.21.6; python_version == '3.7'
 numpy==1.24.3; python_version == '3.8'
 numpy==1.25.0; python_version >= '3.9'
 Pillow==9.5.0
 protobuf==3.19.4  # TensorFlow requires protobuf<3.20 (b/182876485)
 pyopengl==3.1.7
 pyparsing==3.1.0
 requests==2.31.0
-scipy==1.7.3; python_version == '3.7'
-scipy==1.10.1; python_version >= '3.8'
+scipy==1.10.1
 setuptools==68.0.0
 tqdm==4.65.0

setup.py

@@ -193,7 +193,7 @@ def is_excluded(s):
         'License :: OSI Approved :: Apache Software License',
     ],
     keywords='machine learning control physics MuJoCo AI',
-    python_requires='>=3.7',
+    python_requires='>=3.8',
     install_requires=[
         'absl-py>=0.7.0',
         'dm-env',