Fix 'make docker' command and remove broken commands in the readme

Author: caroline-ttd

Dockerfile.dev

@@ -1,3 +1,3 @@
-FROM python:3.6
+FROM python:3.8
 COPY . /build
 RUN pip install --no-cache-dir -e /build[dev]

README.md

@@ -26,22 +26,12 @@ For documentation on usage, see the [UID2 SDK for Python Reference Guide](https:
 
 ## Example Usage
 
-To run all the example applications:
 
-```
-make examples BASE_URL=https://prod.uidapi.com AUTH_KEY=my-auth-key SECRET_KEY=my-secret-key \
-	AD_TOKEN=AgAAAANRdREk+IWqqnQkZ2rZdK0TgSUP/owLryysSkUGZJT+Gy551L1WJMAZA/G2B1UMDQ20WAqwwTu6o9TexWyux0lg0HHIbmJjN6IYwo+42KC8ugaR+PX0y18qQ+3yzkxmJ/ee//4IGu/1Yq4AmO4ArXN6CeszPTxByTkysVqyQVNY2A== \
-	RAW_UID=JCqmlLXpbbu/jTdpB2a1cNAVs8O72eMXPaQzC9Ic9mE= \
-	DOMAIN=example.com
-```
-
-Alternatively, you can run specific examples:
+You can run specific examples:
 
 ```
-make example_client BASE_URL=https://prod.uidapi.com AUTH_KEY=my-auth-key SECRET_KEY=my-secret-key \
-	AD_TOKEN=AgAAAANRdREk+IWqqnQkZ2rZdK0TgSUP/owLryysSkUGZJT+Gy551L1WJMAZA/G2B1UMDQ20WAqwwTu6o9TexWyux0lg0HHIbmJjN6IYwo+42KC8ugaR+PX0y18qQ+3yzkxmJ/ee//4IGu/1Yq4AmO4ArXN6CeszPTxByTkysVqyQVNY2A==
-make example_auto_refresh BASE_URL=https://prod.uidapi.com AUTH_KEY=my-auth-key SECRET_KEY=my-secret-key \
-	AD_TOKEN=AgAAAANRdREk+IWqqnQkZ2rZdK0TgSUP/owLryysSkUGZJT+Gy551L1WJMAZA/G2B1UMDQ20WAqwwTu6o9TexWyux0lg0HHIbmJjN6IYwo+42KC8ugaR+PX0y18qQ+3yzkxmJ/ee//4IGu/1Yq4AmO4ArXN6CeszPTxByTkysVqyQVNY2A==
+python examples/sample_bidstream_client.py BASE_URL=https://operator-integ.uidapi.com AUTH_KEY=my-auth-key SECRET_KEY=my-secret-key
+	DOMAIN_NAME=domain-name AD_TOKEN=ad-token
 ```
 
 ## Development
@@ -55,7 +45,7 @@ make docker
 Run unit tests:
 
 ```
-make test
+Use PyCharm to run the test cases
 ```
 
 Build a bdist wheel: