use dynamic version in gino.__version__

Author: fantix

README.rst

@@ -8,7 +8,7 @@ GINO
 
 .. image:: https://img.shields.io/github/workflow/status/python-gino/gino/test?label=test&logo=github
         :alt: GitHub Workflow Status
-        :target: https://github.com/python-gino/gino/actions?query=workflow%3Apytest
+        :target: https://github.com/python-gino/gino/actions?query=workflow%3Atest
 
 .. image:: https://img.shields.io/codacy/coverage/b6a59cdf5ca64eab9104928d4f9bbb97?logo=codacy
         :alt: Codacy coverage
@@ -28,7 +28,7 @@ GINO
 
 
 GINO - GINO Is Not ORM - is a lightweight asynchronous ORM built on top of
-SQLAlchemy_ core for Python asyncio_. Now (early 2018) GINO supports only one
+SQLAlchemy_ core for Python asyncio_. Now (early 2020) GINO supports only one
 dialect asyncpg_.
 
 * Free software: BSD license

poetry.lock

@@ -27,6 +27,7 @@ python = "^3.5"
 asyncpg = ">=0.18,<1.0"
 SQLAlchemy = "^1.2"
 contextvars = { version = "^2.4", python = "<3.7" }
+importlib_metadata = { version = "^1.3.0", python = "<3.8" }
 
 [tool.poetry.dev-dependencies]
 psycopg2-binary = "^2.8.4"

pyproject.toml

@@ -11,4 +11,16 @@ def create_engine(*args, **kwargs):
     return create_engine(*args, **kwargs)
 
 
-__version__ = "1.0.0-alpha"
+def get_version():
+    try:
+        from importlib.metadata import version
+    except ImportError:
+        from importlib_metadata import version
+    return version("gino")
+
+
+# noinspection PyBroadException
+try:
+    __version__ = get_version()
+except Exception:
+    pass