docs: Bump OpaClusters to v1alpha2

Author: Techassi

docs/modules/opa/examples/getting_started/opa.yaml

@@ -1,5 +1,5 @@
 ---
-apiVersion: opa.stackable.tech/v1alpha1
+apiVersion: opa.stackable.tech/v1alpha2
 kind: OpaCluster
 metadata:
   name: simple-opa

docs/modules/opa/examples/getting_started/opa.yaml.j2

@@ -1,5 +1,5 @@
 ---
-apiVersion: opa.stackable.tech/v1alpha1
+apiVersion: opa.stackable.tech/v1alpha2
 kind: OpaCluster
 metadata:
   name: simple-opa

docs/modules/opa/pages/reference/discovery.adoc

@@ -18,7 +18,7 @@ Given the following OPA cluster:
 
 [source,yaml,subs="normal,callouts"]
 ----
-apiVersion: opa.stackable.tech/v1alpha1
+apiVersion: opa.stackable.tech/v1alpha2
 kind: OpaCluster
 metadata:
   name: {clusterName} # <1>

docs/modules/opa/pages/usage-guide/tls.adoc

@@ -20,7 +20,7 @@ First, create a `SecretClass` that will provide TLS certificates. Here's an exam
 
 [source,yaml]
 ----
-apiVersion: secrets.stackable.tech/v1alpha1
+apiVersion: secrets.stackable.tech/v1alpha2
 kind: SecretClass
 metadata:
   name: opa-tls

docs/modules/opa/pages/usage-guide/user-info-fetcher.adoc

@@ -8,7 +8,7 @@ You can enable the User info fetcher sidecar as follows:
 
 [source,yaml]
 ----
-apiVersion: opa.stackable.tech/v1alpha1
+apiVersion: opa.stackable.tech/v1alpha2
 kind: OpaCluster
 metadata:
   name: opa

docs/modules/opa/partials/nav.adoc

@@ -18,7 +18,7 @@
 *** xref:opa:usage-guide/operations/graceful-shutdown.adoc[]
 * xref:opa:reference/index.adoc[]
 ** xref:opa:reference/crds.adoc[]
-*** {crd-docs}/opa.stackable.tech/opacluster/v1alpha1/[OpaCluster {external-link-icon}^]
+*** {crd-docs}/opa.stackable.tech/opacluster/v1alpha2/[OpaCluster {external-link-icon}^]
 ** xref:opa:reference/discovery.adoc[]
 ** xref:opa:reference/commandline-parameters.adoc[]
 ** xref:opa:reference/environment-variables.adoc[]