refactor!: Rename template to generate and move rebase/upgrade under switch (#116)

This updates the `template` subcommand to be `generate`. The `template`
usage will continue to work as an alias to `generate`. A new `switch`
command is added that will manage both `rpm-ostree rebase` and
`rpm-ostree upgrade` and is fully replacing the respective subcommands
as a breaking change.

The new `switch` command is under the feature flag `switch` and will
currently only build for the `main` branch builds until it is moved as a
default feature (`v0.9.0`).

Closes #159

utils/Cargo.toml

@@ -9,10 +9,10 @@ license.workspace = true
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-atty = "0.2.14"
+atty = "0.2"
 directories = "5"
-process_control = { version = "4.0.3", features = ["crossbeam-channel"] }
-syntect = "5.2.0"
+process_control = { version = "4", features = ["crossbeam-channel"] }
+syntect = "5"
 which = "6"
 
 anyhow.workspace = true