Im/python37 (#334)

* update

* python37 is back

* fix for python37

* another small fix in toml for 3.10

* need semvar notation

* update poetry

.github/workflows/docs.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.8]
+        python-version: [3.9]
 
     steps:
       - name: Checkout github repo

.github/workflows/lint.yml

@@ -1,4 +1,4 @@
-# This workflow will install Python dependencies, run tests and lint with a variety of Python versions
+# This workflow will install Python dependencies, lint with Python 3.9
 # For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
 
 name: lint
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.8, 3.9]
+        python-version: [3.9]
 
     steps:
       - name: Checkout github repo

.github/workflows/notebooks.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.8, 3.9]
+        python-version: [3.7, 3.8, 3.9, 3.10]
 
     steps:
       - name: Checkout github repo (+ download lfs dependencies)

.github/workflows/publish.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.8]
+        python-version: [3.9]
 
     steps:
       - name: Checkout github repo

.github/workflows/test.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.8, 3.9]
+        python-version: [3.7, 3.8, 3.9, "3.10"]
 
     steps:
       - name: Checkout github repo

btk/__init__.py

@@ -4,7 +4,10 @@
 providing a framework to test user defined detection/deblending/measurement
 algorithms.
 """
-from importlib import metadata
+try:
+    from importlib import metadata
+except ImportError:  # for Python<3.8
+    import importlib_metadata as metadata
 
 __author__ = "btk developers"
 __email__ = "[email protected]"