[deps] Disabled prometheus/push so this crate don't need native-tls

[sgirones]

The push feature for the prometheus crate depends on reqwest, which depends on native-tls by default.

Since we are not using the prometheus/push feature for now, let's disable it and come back to it once the funcionality becomes necessary.

This is necessary for surrealdb to not depend on native-tls and rely on rustls completely

[tobiemh]

@sgirones is this what was causing the nightly build failures?

[sgirones]

In part, yes: when we switched to ubuntu-latest, the cargo build was unable to find the openssl-dev dependency. We could try to install the necessary ubuntu package, but given we want to get rid of native-tls, let's try to accomplish it.

The nice side effect is that we may be able to get rid of the windows' dependencies installation too.