implement regal based rego file validation

go.mod

@@ -1,6 +1,8 @@
 module github.com/eclipse-xpanse/policy-man
 
-go 1.20
+go 1.21
+
+toolchain go1.21.1
 
 require (
 	github.com/gin-contrib/logger v0.2.6
@@ -11,10 +13,15 @@ require (
 	github.com/spf13/cobra v1.7.0
 	github.com/spf13/viper v1.16.0
 	github.com/stretchr/testify v1.8.4
+	github.com/styrainc/regal v0.9.0
+	github.com/swaggo/files v1.0.1
+	github.com/swaggo/gin-swagger v1.6.0
+	github.com/swaggo/swag v1.16.2
 	golang.org/x/sync v0.3.0
 )
 
 require (
+	dario.cat/mergo v1.0.0 // indirect
 	github.com/KyleBanks/depth v1.2.1 // indirect
 	github.com/OneOfOne/xxhash v1.2.8 // indirect
 	github.com/agnivade/levenshtein v1.1.1 // indirect
@@ -56,19 +63,16 @@ require (
 	github.com/pelletier/go-toml/v2 v2.0.8 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_golang v1.16.0 // indirect
-	github.com/prometheus/client_model v0.3.0 // indirect
-	github.com/prometheus/common v0.42.0 // indirect
+	github.com/prometheus/client_model v0.4.0 // indirect
+	github.com/prometheus/common v0.44.0 // indirect
 	github.com/prometheus/procfs v0.10.1 // indirect
-	github.com/rcrowley/go-metrics v0.0.0-20200313005456-10cdbea86bc0 // indirect
+	github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475 // indirect
 	github.com/rs/zerolog v1.29.1 // indirect
 	github.com/spf13/afero v1.9.5 // indirect
 	github.com/spf13/cast v1.5.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/subosito/gotenv v1.4.2 // indirect
-	github.com/swaggo/files v1.0.1 // indirect
-	github.com/swaggo/gin-swagger v1.6.0 // indirect
-	github.com/swaggo/swag v1.16.2 // indirect
 	github.com/tchap/go-patricia/v2 v2.3.1 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.2.11 // indirect