This is a breaking change, requiring users of `featureGates` to change
from a `listOf str` to `attrsOf bool`.
Before:
```nix
featureGates = [ "EphemeralContainers" ];
extraOpts = pkgs.lib.concatStringsSep " " (
[
"--container-runtime=remote"
''--feature-gates="CSIMigration=false"''
});
```
After:
```nix
featureGates = {EphemeralContainers = true; CSIMigration=false;};
```
This is much nicer, and sets us up for later work of migrating to
configuration files for other services, like e.g. has been happening
with kubelet (see: #290119).
Signed-off-by: Christina Sørensen <christina@cafkafk.com>
32ca66f3ed