Unexpected error when resolving project in the current directory

$ cat PklProject
amends "pkl:Project"
$ cat main.pkl
foo {
  bar = 1
}
$ tree .
.
├── PklProject
└── main.pkl

1 directory, 2 files
$ pkl project resolve .
An unexpected error has occurred. Would you mind filing a bug report?

java.lang.NullPointerException
    at org.pkl.cli.CliProjectResolver.doRun(CliProjectResolver.kt:47)
    at org.pkl.commons.cli.CliCommand.run(CliCommand.kt:45)
    at org.pkl.cli.commands.ProjectCommand$Companion$ResolveCommand.run(ProjectCommand.kt:71)
    at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:198)
    at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:211)
    at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:211)
    at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:18)
    at com.github.ajalt.clikt.core.CliktCommand.parse(CliktCommand.kt:400)
    at com.github.ajalt.clikt.core.CliktCommand.parse$default(CliktCommand.kt:397)
    at com.github.ajalt.clikt.core.CliktCommand.main(CliktCommand.kt:415)
    at com.github.ajalt.clikt.core.CliktCommand.main(CliktCommand.kt:440)
    at org.pkl.cli.Main$main$1.invoke(Main.kt:52)
    at org.pkl.cli.Main$main$1.invoke(Main.kt:40)
    at org.pkl.commons.cli.CliMainKt.cliMain(CliMain.kt:31)
    at org.pkl.cli.Main.main(Main.kt:40)
$ cd ..
$ pkl project resolve pkl-bug-report
pkl-bug-report/PklProject.deps.json
$ tree pkl-bug-report
pkl-bug-report
├── PklProject
├── PklProject.deps.json
└── main.pkl

1 directory, 3 files
apple / pkl

Unexpected error when resolving project in the current directory #531
