"$" in code examples in Readme prevents simple copy/paste

[agirlnamedsophia]

Hi! First, huge fan of sops - this is a silly "non-issue" kind of nit, but I noticed that the code examples inconsistently had the shell prompt included so when you copy / paste blocks of code into your terminal (yes yes, not good form, always verify before hitting enter) the prompt would be there for some lines. I'd like to open a PR to remove those if that's alright. Cheers!

[felixfontein]

Thanks @agirlnamedsophia! While I agree that they aren't needed in some cases, in others they have to stay IMO, namely when commands are combined with output, like here:

$ cat ~/.aws/credentials
[default]
aws_access_key_id = AKI.....
aws_secret_access_key = mw......

Removing the $ here makes the example a lot harder to read.

This would increase inconsistence though, since then there are a lot examples that do not use $ and a lot that do use $. Right now $ is very consistently (at least I didn't find any exceptions) used when commands that are executed are marked in code blocks.