Upgrade architecture + 5.0 Bot API (#469)

Upgrade architecture + 5.0 Bot API (#469)
* Moved `methods`, `types` and `client` to root package
* Removed update handler from routers to dispatcher
* Reworked events propagation mechanism to handlers
* Reworked inner middlewares logic (very small change)
* Updated to Bot API 5.0
* Initial migration from MkDocs to Sphinx + config for readthedocs

.github/workflows/docs.yml

@@ -19,7 +19,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install --upgrade pip poetry==1.0
+          python -m pip install --upgrade pip poetry==1.1.4
           poetry install
           mkdir -p reports
 

.github/workflows/tests.yml

@@ -13,6 +13,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       max-parallel: 6
+      fail-fast: false
       matrix:
         os:
           - ubuntu-latest
@@ -21,6 +22,7 @@ jobs:
         python-version:
           - 3.7
           - 3.8
+          - 3.9
 
     steps:
       - uses: actions/checkout@master
@@ -32,7 +34,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install --upgrade pip poetry==1.0
+          python -m pip install --upgrade pip poetry==1.1.4
           poetry install
 
       - name: Lint code