fix venv executable name in readme

shorten nxy-db-dump.service
fix irc3 requirement (async/await became keywords with python3.7, so mrhanky's older version will no longer work)

README.md

@@ -25,7 +25,7 @@ Clone git repo, create virtual env, activate it and install dependencies:
 ```sh
 git clone https://gitfap.de/mrhanky/nxy.git
 python3 -m venv env
-source env/bin/active
+source env/bin/activate
 pip install -U -r nxy/requirements.txt
 ```
 
@@ -69,4 +69,4 @@ Finally run nxy:
 
 ```
 python3 -m bot
-```
+```