Fix panic when version block has a comma in between versions

[kirillzh]

This was caused by this PR.

Searching or installing corretto package no longer works, running hermit search corretto errors this:

panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x1c8 pc=0x100c679dc]

goroutine 1 [running]:
github.com/cashapp/hermit/app.Main.func3()
	/home/runner/work/hermit/hermit/app/main.go:149 +0x58
panic({0x100f49700, 0x101396500})
	/home/runner/.cache/hermit/pkg/go-1.19.1/src/runtime/panic.go:884 +0x204
github.com/cashapp/hermit/manifest.(*Resolver).Search(0x140003a3a90, {0x100fe6ec8, 0x1400015a200}, {0x14000423970?, 0x14000162700?})
	/home/runner/work/hermit/hermit/manifest/resolver.go:231 +0x17c
github.com/cashapp/hermit.(*Env).Search(0x140003fc140?, 0x0?, {0x14000423970, 0x8})
	/home/runner/work/hermit/hermit/env.go:1045 +0x48
github.com/cashapp/hermit/app.(*searchCmd).Run(0x14000394150, 0x1400015a200, 0x140003fc140, 0x1?)
	/home/runner/work/hermit/hermit/app/search_cmd.go:87 +0xb8
reflect.Value.call({0x100f3a880?, 0x14000394150?, 0x14000163178?}, {0x100de0cc6, 0x4}, {0x1400039ca80, 0x3, 0x100d7e1f0?})
	/home/runner/.cache/hermit/pkg/go-1.19.1/src/reflect/value.go:584 +0x688
reflect.Value.Call({0x100f3a880?, 0x14000394150?, 0x100f52400?}, {0x1400039ca80?, 0x1400042ee80?, 0x9?})
	/home/runner/.cache/hermit/pkg/go-1.19.1/src/reflect/value.go:368 +0x90
github.com/alecthomas/kong.callMethod({0x100de0558, 0x3}, {0x100f99c80?, 0x14000394150?, 0x3?}, {0x100f3a880?, 0x14000394150?, 0x1400047fbc0?}, 0x100fdf2a0?)
	/home/runner/go/pkg/mod/github.com/alecthomas/[email protected]/callbacks.go:97 +0x3e4
github.com/alecthomas/kong.(*Context).RunNode(0x140003fe180, 0x140003b6d20, {0x14000163990, 0x8, 0x8})
	/home/runner/go/pkg/mod/github.com/alecthomas/[email protected]/context.go:735 +0x460
github.com/alecthomas/kong.(*Context).Run(0x100fc2ec0?, {0x14000163990?, 0x5?, 0x5?})
	/home/runner/go/pkg/mod/github.com/alecthomas/[email protected]/context.go:760 +0x144
github.com/cashapp/hermit/app.Main({{0x1400002a480, 0x10}, 0x3, {0x140000283c0, 0x3a}, {0x1400001fa10, 0x3, 0x3}, {0x14000292000, 0x13, ...}, ...})
	/home/runner/work/hermit/hermit/app/main.go:279 +0x189c
main.main()
	/home/runner/work/hermit/hermit/cmd/hermit/main.go:28 +0x1cc

Searching and installing other packages works well. I am wondering if this is caused by a comma here? https://github.com/cashapp/hermit-packages/pull/225/files#r1001268100

[alecthomas]

This is fixed now - it was the spurious comma. I'm not sure why the parser didn't error, rather than just panicking. I'll have to look into that.