Describe the bug
Unable to find documentation to convert dataFrom transform actions in 0.18.2 to the correct replacement for this.

Existing process would uppercase secret names as key names, and convert - to _, but this transform does not happen in 0.18.2

To Reproduce

1. Create GCP SecretManagerSecret named dev-my-thing with tags dev and myapp in cluser running External Secrets Operator 0.17.0
2. Create an ExternalSecret using ExternalSecretOperator 0.17.0 as follows

apiVersion: external-secrets.io/v1
kind: ExternalSecret
metadata:
  name: dev-my-app-multi-es
  namespace: myns
spec:
  refreshInterval: 300s
  secretStoreRef:
    name: external-secrets-store
    kind: ClusterSecretStore
  target:
    name: dev-my-app-secret
  dataFrom:
  - find:
      tags:
        env: dev
        component: myapp
    rewrite:
    - regexp:
        source: ^dev-(.*)
        target: "$1"
      transform:
        template: '{{ .value | upper | replace "-" "_" }}'

3. Get secret and observe that keys in k8s secrets are all uppercase with - replaced by _, with dev- removed
4. Upgrade to 0.18.2
5. Observe that keys in k8s secrets still have dev- removed but are now in lowercase with - present

Expected behavior
With the above config, I expect a SecretManagerSecret named dev-my-thing to result in a key named MY_THING in my kubernetes secret

Additional context
I've checked https://external-secrets.io/latest/guides/templating/ and https://external-secrets.io/latest/guides/datafrom-rewrite/ and I don't see transform examples there. I do see an example for replacing invalid characters, but this doesn't include an upper helper.

The templating examples at https://external-secrets.io/v0.18.2/guides/templating/ seem to require that I know the names of all of the keys that will be in the secret, but we use dataFrom to avoid having to enumerate all of the SecretManagerSecrets we wish to populate into the k8s secret.

There is nothing in the external-secrets pod logs that indicates why this transform is no longer taking place that I can see