default vc to block v3 endpoint and deprecate block-v3 flag (#5292)

* default vc to block v3 endpoint and deprecate block-v3 flag

* kick off ci

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into default-vc-to-block-v3-endpoint

* fix formatting in cli docs

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into default-vc-to-block-v3-endpoint

* Resolve merge conflicts

* resolve conflicts

* merge

* merge

* revert

* retry

* fix

* Merge branch 'unstable' into default-vc-to-block-v3-endpoint

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into default-vc-to-block-v3-endpoint

* fix issues w/ fallback sim

testing/simulator/src/cli.rs

@@ -77,7 +77,6 @@ pub fn cli_app() -> Command {
                 )
                 .arg(
                     Arg::new("vc-count")
-                        .short('c')
                         .long("vc-count")
                         .action(ArgAction::Set)
                         .default_value("3")