Novice user experience

[xldenis]

I'm just trying out drom for a small project and wanted to open an issue with the various problems / issues I'm encountering. I hope this will be useful for the maintainers.

1. The README in this project contains no example of the installation / usage of drom. I think a simple: opam install drom; drom new project; drom build example would be great. Could also be on the website homepage.
2. My drom generated project fails to build with the following error:

drom: Entering directory '/Users/xavier/Code/why3-tools'
# Run eval $(opam env) to update the current shell environment
[NOTE] It seems you have not updated your repositories for a while. Consider updating them with:
       opam update

[ERROR] Package conflict!
  * Missing dependency:
    - ocaml-base-compiler = 4.10.0 | ocaml-system < 4.10.1~ | ocaml-variants < 4.10.1~
    unmet availability conditions: '!(os = "macos" & arch = "arm64")'
    unmet availability conditions, e.g. 'sys-ocaml-version = "4.10.0"'
    unmet availability conditions, e.g. '!(os = "macos" & arch = "arm64")'

No solution found, exiting
Error: Command 'opam install -y ocaml.4.10.0' exited with error code 20

I would have expected drom to set up my project specific opam switch and load it if necessary.

3. No lockfiles? One of the biggest things I was hoping drom would do is fix one of the major issues with opam by enabling lock files by default but this does not seem to be the case?
4. No way to specify pinned dependencies in package.toml?