Issues with Nimble Installation

https://github.com/crashappsec/con4m/blob/45f50217b465968e1ded0f81dca8f74c65eedb5c/con4m.nimble#L12

I think the `~=` should be either `==` or `>=`. The ampersand doesn't seem to be valid for nimble.

```
# nimble install https://github.com/crashappsec/con4m
Downloading https://github.com/crashappsec/con4m using git
Tip: 2 messages have been suppressed, use --verbose to show them.
Error: Could not read package info file in /tmp/nimble_14/githubcom_crashappseccon4m/con4m.nimble;
... Reading as ini file failed with:
... Invalid section: .
... Evaluating as NimScript file failed with:
... Unable to parse dependency version range: Unexpected char in version range ' ~= 0.2.2': ~.
```