Bump and specify Terraform provider versions (#1736)

#1723 is trying a major version bump of the Google Terraform providers,
which changed the way GKE taints are defined, so I've done the bumps
manually with the required changes.

`terraform plan` shows it's adding some new `terraform_labels` to the
Cloud Run services, with metadata about the Cloud Deploy pipeline which
includes the current 'release-id' which hopefully isn't a problem when
it changes outside of Terraform.

I've also explicitly added the `required_providers` to the root modules
(see the [best
practices](https://developer.hashicorp.com/terraform/language/providers/requirements#best-practices-for-provider-versions)),
so hopefully renovate-bot won't blindly do breaking changes in the
future.

deployment/terraform/environments/oss-vdb-test/main.tf

@@ -19,4 +19,23 @@ terraform {
     bucket = "oss-vdb-tf"
     prefix = "oss-vdb-test"
   }
+
+  required_providers {
+    google = {
+      source  = "hashicorp/google"
+      version = "~> 5.2.0"
+    }
+    google-beta = {
+      source  = "hashicorp/google-beta"
+      version = "~> 5.2.0"
+    }
+    external = {
+      source  = "hashicorp/external"
+      version = "~> 2.3.1"
+    }
+    null = {
+      source  = "hashicorp/null"
+      version = "~> 3.2.1"
+    }
+  }
 }

deployment/terraform/environments/oss-vdb/main.tf

@@ -19,4 +19,22 @@ terraform {
     bucket = "oss-vdb-tf"
     prefix = "oss-vdb"
   }
+  required_providers {
+    google = {
+      source  = "hashicorp/google"
+      version = "~> 5.2.0"
+    }
+    google-beta = {
+      source  = "hashicorp/google-beta"
+      version = "~> 5.2.0"
+    }
+    external = {
+      source  = "hashicorp/external"
+      version = "~> 2.3.1"
+    }
+    null = {
+      source  = "hashicorp/null"
+      version = "~> 3.2.1"
+    }
+  }
 }

deployment/terraform/modules/osv/workers_gke.tf

@@ -107,11 +107,11 @@ resource "google_container_node_pool" "highend" {
       workloadType = "highend"
     }
 
-    taint = [{
+    taint {
       effect = "NO_EXECUTE"
       key    = "workloadType"
       value  = "highend"
-    }]
+    }
 
   }
 }
@@ -143,11 +143,11 @@ resource "google_container_node_pool" "importer_pool" {
       workloadType = "importer-pool"
     }
 
-    taint = [{
+    taint {
       effect = "NO_EXECUTE"
       key    = "workloadType"
       value  = "importer-pool"
-    }]
+    }
   }
 }