feat: add the arm project type [FIX-488]

The ARM parser plugin reports "arm" as its config file project type, so it
is a filterable type in its own right rather than something folded onto
another family.

Author: liamcervante

pkg/project/project.go

@@ -40,6 +40,7 @@ const (
 	CDKPython      Type = "cdk_python"
 	CiscoStacks    Type = "cisco_stacks"
 	Kubernetes     Type = "kubernetes"
+	ARM            Type = "arm"
 )
 
 // IsCDK reports whether a project is one of the CDK languages.
@@ -101,7 +102,7 @@ func Resolve(t Type, dir string) Type {
 // display order. It is deliberately coarser than the full set above:
 // NormalizeForFilter folds the niche and derived types onto the family a user
 // would recognise, so policies are written against a short, stable list.
-var Filterable = []Type{Terraform, Terragrunt, CloudFormation, Kubernetes}
+var Filterable = []Type{Terraform, Terragrunt, CloudFormation, ARM, Kubernetes}
 
 // NormalizeForFilter collapses a project type onto the Filterable set, so a
 // policy targeting "cloudformation" also covers the CDK variants that the

pkg/project/project_test.go

@@ -20,6 +20,7 @@ func TestResolve(t *testing.T) {
 		{"terragrunt is unchanged", Terragrunt, nil, Terragrunt},
 		{"cloudformation is unchanged", CloudFormation, nil, CloudFormation},
 		{"kubernetes is unchanged", Kubernetes, nil, Kubernetes},
+		{"arm is unchanged", ARM, nil, ARM},
 
 		// Cisco Stacks has its own parser plugin, so unlike filtering this must
 		// not fold it onto terraform.
@@ -69,6 +70,7 @@ func TestParserFamily(t *testing.T) {
 		{Terragrunt, Terragrunt},
 		{CloudFormation, CloudFormation},
 		{Kubernetes, Kubernetes},
+		{ARM, ARM},
 		{CiscoStacks, CiscoStacks},
 		{CDKTypeScript, CloudFormation},
 		{CDKJavaScript, CloudFormation},
@@ -111,6 +113,7 @@ func TestNormalizeForFilter(t *testing.T) {
 		{"terragrunt stays distinct", Terragrunt, Terragrunt},
 		{"cloudformation is unchanged", CloudFormation, CloudFormation},
 		{"kubernetes is unchanged", Kubernetes, Kubernetes},
+		{"arm is unchanged", ARM, ARM},
 
 		{"untyped project folds to terraform", Unknown, Terraform},
 		{"cisco stacks folds to terraform", CiscoStacks, Terraform},
@@ -135,7 +138,7 @@ func TestNormalizeForFilter(t *testing.T) {
 func TestNormalizeForFilter_LandsOnFilterableSet(t *testing.T) {
 	all := []Type{
 		Unknown, Terraform, Terragrunt, CloudFormation,
-		CDKTypeScript, CDKJavaScript, CDKPython, CiscoStacks, Kubernetes,
+		CDKTypeScript, CDKJavaScript, CDKPython, CiscoStacks, Kubernetes, ARM,
 	}
 
 	for _, projectType := range all {