Use importlib.metadata to surface Basilisp version (#743)

Fixes #617

CHANGELOG.md

@@ -27,10 +27,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  * Fixed issue with import modules aliasing using ns eval (#719)
  * Fix issue with `ns-resolve` throwing an error on macros (#720)
  * Fix issue with py module `readerwritelock` locks handling (#722)
- * Fix issue with basilisp.io/writer :append mode not working (#741).
+ * Fix issue with basilisp.io/writer :append mode not working (#741)
 
 ### Removed
  * Removed the dependency `astor` for versions of Python 3.9+ (#736)
+ * Removed `basilisp.__version__` in favor of using `importlib.metadata` for version info (#617)
 
 ## [v0.1.0a2]
 ### Added

src/basilisp/cli.py

@@ -1,5 +1,5 @@
 import argparse
-import importlib
+import importlib.metadata
 import io
 import os
 import sys
@@ -430,9 +430,8 @@ def _add_test_subcommand(parser: argparse.ArgumentParser) -> None:
 
 
 def version(_, __):
-    from basilisp.__version__ import __version__
-
-    print(f"Basilisp {__version__}")
+    v = importlib.metadata.version("basilisp")
+    print(f"Basilisp {v}")
 
 
 @_subcommand("version", help="print the version of Basilisp", handler=version)

src/basilisp/lang/runtime.py

@@ -1,7 +1,7 @@
 import contextlib
 import decimal
 import functools
-import importlib
+import importlib.metadata
 import inspect
 import itertools
 import logging
@@ -72,6 +72,10 @@
 NS_VAR_NS = CORE_NS
 REPL_DEFAULT_NS = "basilisp.user"
 SUPPORTED_PYTHON_VERSIONS = frozenset({(3, 8), (3, 9), (3, 10), (3, 11), (3, 12)})
+BASILISP_VERSION_STRING = importlib.metadata.version("basilisp")
+BASILISP_VERSION = vec.vector(
+    (int(s) if s.isdigit() else s) for s in BASILISP_VERSION_STRING.split(".")
+)
 
 # Public basilisp.core symbol names
 COMPILER_OPTIONS_VAR_NAME = "*compiler-options*"
@@ -2118,8 +2122,6 @@ def in_ns(s: sym.Symbol):
     )
 
     # Version info
-    from basilisp.__version__ import VERSION
-
     Var.intern(
         CORE_NS_SYM,
         sym.symbol(PYTHON_VERSION_VAR_NAME),
@@ -2137,7 +2139,7 @@ def in_ns(s: sym.Symbol):
     Var.intern(
         CORE_NS_SYM,
         sym.symbol(BASILISP_VERSION_VAR_NAME),
-        vec.vector(VERSION),
+        BASILISP_VERSION,
         dynamic=True,
         meta=lmap.map(
             {