SCons: Bump minimum version of SCons to 4.0 & Python to 3.8

[Repiteo]

• Supersedes Bump minimum SCons version to 4.0 #85968
• Supersedes SCons: Bump minimum Python version to 3.8 #98907

As discussed in this RocketChat thread¹, the bump to Ubuntu 22.04 for our GitHub Actions have raised the lower bounds of support for both Python and SCons. As our current minimum versions for both (3.1.2 for SCons & 3.6 for Python) are well into EOL as-is, it feels ideal to bump the versions in tandem. In contrast to previous PRs trying to have other changes in tandem, this is strictly focused on bumping the minimum versions

Immediate benefits include:

• Having a minimum Python version that matches the minimum supported version for mypy.
• Bumping Ruff's minimum version to 3.8 as well, now matching versions
• Single baseline OS for Linux builds

Footnotes

1. https://chat.godotengine.org/channel/buildsystem?msg=Wuq39TCvaHTSiSAuL ↩

[akien-mga]

You can add at least those changes too:

diff --git a/SConstruct b/SConstruct
index ee34d421e0..0eba4c3f7b 100644
--- a/SConstruct
+++ b/SConstruct
@@ -1060,13 +1060,6 @@ if env["vsproj"]:
     env.vs_srcs = []
 
 if env["compiledb"]:
-    if env.scons_version < (4, 0, 0):
-        # Generating the compilation DB (`compile_commands.json`) requires SCons 4.0.0 or later.
-        print_error(
-            "The `compiledb=yes` option requires SCons 4.0 or later, but your version is %s." % scons_raw_version
-        )
-        Exit(255)
-
     env.Tool("compilation_db")
     env.Alias("compiledb", env.CompilationDatabase())
 
diff --git a/methods.py b/methods.py
index 64c3839718..1fb6f367b0 100644
--- a/methods.py
+++ b/methods.py
@@ -409,8 +409,7 @@ def use_windows_spawn_fix(self, platform=None):
             "shell": False,
             "env": env,
         }
-        if sys.version_info >= (3, 7, 0):
-            popen_args["text"] = True
+        popen_args["text"] = True
         proc = subprocess.Popen(cmdline, **popen_args)
         _, err = proc.communicate()
         rv = proc.wait()