kubeseal fails to parse a yaml file - panic to parse event

The issue I'm facing is when running the following command: ` kubeseal --scope cluster-wide --format=yaml < secret.yaml`

```
jsanabri@Franciscos-MacBook-Pro /tmp % kubeseal --scope cluster-wide --format=yaml < secret.yaml
panic: attempted to parse unknown event: none [recovered]
panic: attempted to parse unknown event: none

goroutine 1 [running]:
gopkg.in/yaml%2ev2.handleErr(0xc000019998)
/Users/brew/Library/Caches/Homebrew/go_mod_cache/pkg/mod/gopkg.in/yaml.v2@v2.4.0/yaml.go:249 +0x6d
panic({0x1e3eea0, 0xc000720650})
/usr/local/Cellar/go/1.18.3/libexec/src/runtime/panic.go:838 +0x207
gopkg.in/yaml%2ev2.(*parser).parse(0xc00013e000)
/Users/brew/Library/Caches/Homebrew/go_mod_cache/pkg/mod/gopkg.in/yaml.v2@v2.4.0/decode.go:158 +0x154
gopkg.in/yaml%2ev2.(*Decoder).Decode(0xc000019a08, {0x1e012e0?, 0x2b8a588})
/Users/brew/Library/Caches/Homebrew/go_mod_cache/pkg/mod/gopkg.in/yaml.v2@v2.4.0/yaml.go:122 +0x107
github.com/bitnami-labs/sealed-secrets/pkg/multidocyaml.isMultiDocumentYAML({0xc000134200, 0xfa, 0x200})
/private/tmp/kubeseal-20220602-72017-lkgeub/pkg/multidocyaml/multidocyaml.go:14 +0x205
github.com/bitnami-labs/sealed-secrets/pkg/multidocyaml.EnsureNotMultiDoc({0xc000134200?, 0xc0001a8000?, 0xc0004826e0?})
/private/tmp/kubeseal-20220602-72017-lkgeub/pkg/multidocyaml/multidocyaml.go:19 +0x1e
main.readSecret({0xb08aa18, 0xc0004826e0}, {0x21fd1a0?, 0xc0001a8000?})
/private/tmp/kubeseal-20220602-72017-lkgeub/cmd/kubeseal/main.go:146 +0x5d
main.seal({0x21fd1a0, 0xc0001a8000}, {0x21fd1c0, 0xc0001a8008}, {0xc000268150, {0x21fcb00, 0xc00019e9c0}, {0xc0001a2e00, 0x3, 0x4}, ...}, ...)
/private/tmp/kubeseal-20220602-72017-lkgeub/cmd/kubeseal/main.go:262 +0x109
main.run({0x220ebe8, 0xc0001a6000}, {0x21fd1c0?, 0xc0001a8008}, {0x0, 0x0}, {0x0, 0x0}, {0x0, 0x0}, ...)
/private/tmp/kubeseal-20220602-72017-lkgeub/cmd/kubeseal/main.go:766 +0xc4e
main.main()
/private/tmp/kubeseal-20220602-72017-lkgeub/cmd/kubeseal/main.go:773 +0x33b
```
Here basically I'm logged into my Openshift cluster, and running the command to encrypt a Instana agent license key.

**Expected behavior**

Getting an output from the yaml file, with the encrypted elements.
For example:

```
---
apiVersion: bitnami.com/v1alpha1
kind: SealedSecret
metadata:
annotations:
sealedsecrets.bitnami.com/cluster-wide: "true"
creationTimestamp: null
name: instana-agent
namespace: observe
spec:
encryptedData:
key: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
template:
data: null
metadata:
annotations:
sealedsecrets.bitnami.com/cluster-wide: "true"
creationTimestamp: null
labels:
app.kubernetes.io/name: instana-agent
app.kubernetes.io/version: 1.2.29
name: instana-agent
namespace: observe
type: Opaque
---

```

**Additional context**

Using MacOS Monterey 12.4, I have been using the same command over and over again in the past, with no issues. It just suddenly stop working.
I also gave installed `go1.18.3 darwin/amd64`

Read pkg/multidocyaml/multidocyaml.go and cmd/kubeseal/main.go at the stack-trace locations, then reproduce the supplied kubeseal command with the actual secret.yaml. Determine what input or parser handling triggers the panic. Done means the command reports a usable error or produces the expected SealedSecret without panicking.

Written by the indexing model from the issue text.