[POR-1007] `v2beta1` will replace all instances of `${{ porter.env.FOOBAR }}` with the env var from `PORTER_APPLY_FOOBAR` (#2833)

* add os env support for v2beta1

* fix regex

cli/cmd/preview/v2beta1/addon_resource.go

@@ -11,7 +11,9 @@ func (a *AddonResource) GetName() string {
 }
 
 func (a *AddonResource) GetDependsOn() []string {
-	var dependsOn []string
+	dependsOn := []string{
+		"get-env",
+	}
 
 	if a == nil || a.DependsOn == nil {
 		return dependsOn

cli/cmd/preview/v2beta1/app_resource.go

@@ -74,7 +74,7 @@ func (a *AppResource) getV1Resource(b *Build) (*types.Resource, error) {
 
 	return &types.Resource{
 		Name:      a.GetName(),
-		DependsOn: append([]string{b.GetName()}, a.GetDependsOn()...),
+		DependsOn: append([]string{"get-env", b.GetName()}, a.GetDependsOn()...),
 		Source: map[string]any{
 			"name":    a.Chart.GetName(),
 			"repo":    a.Chart.GetURL(),

cli/cmd/preview/v2beta1/apply.go

@@ -3,6 +3,7 @@ package v2beta1
 import (
 	"context"
 	"fmt"
+	"regexp"
 
 	api "github.com/porter-dev/porter/api/client"
 	"github.com/porter-dev/porter/cli/cmd/config"
@@ -28,6 +29,10 @@ type PreviewApplier struct {
 }
 
 func NewApplier(client *api.Client, raw []byte, namespace string) (*PreviewApplier, error) {
+	// replace all instances of ${{ porter.env.FOO }} with { .get-env.FOO }
+	re := regexp.MustCompile(`\$\{\{\s*porter\.env\.(.*)\s*\}\}`)
+	raw = re.ReplaceAll(raw, []byte("{.get-env.$1}"))
+
 	parsed := &PorterYAML{}
 
 	err := yaml.Unmarshal(raw, parsed)
@@ -147,6 +152,12 @@ func (a *PreviewApplier) DowngradeToV1() (*types.ResourceGroup, error) {
 
 	v1File := &types.ResourceGroup{
 		Version: "v1",
+		Resources: []*types.Resource{
+			{
+				Name:   "get-env",
+				Driver: "os-env",
+			},
+		},
 	}
 
 	buildRefs := make(map[string]*Build)

cli/cmd/preview/v2beta1/build.go

@@ -164,6 +164,9 @@ func (b *Build) getV1BuildImage() (*types.Resource, error) {
 		Target: map[string]any{
 			"app_name": b.GetName(),
 		},
+		DependsOn: []string{
+			"get-env",
+		},
 		Config: rawConfig,
 	}, nil
 }
@@ -184,6 +187,7 @@ func (b *Build) getV1PushImage() (*types.Resource, error) {
 		Name:   b.GetName(),
 		Driver: "push-image",
 		DependsOn: []string{
+			"get-env",
 			fmt.Sprintf("%s-build-image", b.GetName()),
 		},
 		Target: map[string]any{