repro-env v0.3.0 released

[kpcyrd]

hello list,

I've released v0.3.0 of repro-env:

https://github.com/kpcyrd/repro-env/releases/tag/v0.3.0

It removes the need for a working shared-mime-info environment, the only 
runtime dependencies are now:

- Linux unprivileged user-namespaces enabled
- podman installed
- catatonit installed

The sha256 of the official v0.3.0 binary is:

3e5777d952a47d5562d309fd6cb861c0aa4a6a5e45a8aaefa073e702834e9e6d

Github actions built a binary with the same sha256 (unfortunately I 
can't ingest the log into web.archive.org and the maximum retention on 
github is 90 days):

https://github.com/kpcyrd/repro-env/actions/runs/5558665895/jobs/10154023918

You can confirm this yourself by building a bit-for-bit identical binary 
from source like this:

```
git clone https://github.com/kpcyrd/repro-env
cd repro-env
git checkout v0.3.0
make
sha256sum target/x86_64-unknown-linux-musl/release/repro-env
```

The Debian example is failing unfortunately due to 504's from 
snapshot.debian.org:

https://github.com/kpcyrd/repro-env/actions/runs/5558665895/jobs/10154118574

You may want to stick to compilers from archive.archlinux.org for now, 
or use an image like docker.io/library/rust:1-alpine or 
docker.io/library/golang:1-alpine with no further packages installed.

cheers,
kpcyrd