Specify minimum Docker compose version of 1.26.0

Starting from Docker compose 1.26.0 .env file is parsed with dotenv
Python module which adds support of trailing comments used in
.env.example. With previous versions trailing comments are interpreted
as part of environment variable's string value, so you should manually
remove trailing comments from .env for the correct behaviour.

Signed-off-by: alfred richardsn <rchrdsn@protonmail.ch>

README.md

@@ -41,7 +41,7 @@ cp .env.example .env
 5. Create a file containing Telegram bot's API token with filename specified in ```TOKEN_FILENAME``` from ```.env``` (example in [secrets/tbtoken](secrets/tbtoken)).
 6. *(Optional)* If you're going to support escrow, set ```ESCROW_ENABLED=true``` in ```.env``` and create a file containing JSON mapping blockchain names to bot's WIF and API nodes with filename specified in ```ESCROW_FILENAME``` from ```.env``` (example in [secrets/escrow.json](secrets/escrow.json)).
 7. Create a file containing database password with filename specified in ```DATABASE_PASSWORD_FILENAME``` from ```.env``` (example in [secrets/dbpassword](secrets/dbpassword)).
-8. Install [Docker Compose](https://docs.docker.com/compose/install/).
+8. Install [Docker Compose](https://docs.docker.com/compose/install/) version no less than 1.26.0.
 9. Start container:
 ```bash
 docker-compose up --build