Character restrictions in action names were unduly oppressive (#24642)

* Character restrictions in action names were unduly oppressive

* OK but what about SOME oppression

* Test updates for our new action name rules

.changelog/24642.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+actions: Nomad Actions names now accept a wider range of names
+```

nomad/structs/actions.go

@@ -16,8 +16,8 @@ import (
 	"github.com/hashicorp/go-multierror"
 )
 
-// validJobActionName is used to validate a job action name.
-var validJobActionName = regexp.MustCompile("^[a-zA-Z0-9-]{1,128}$")
+// validJobActionName is used to validate a action name.
+var validJobActionName = regexp.MustCompile(`^[^\x00\s]{1,128}$`)
 
 type Action struct {
 	Name    string

nomad/structs/actions_test.go

@@ -178,12 +178,28 @@ func TestAction_Validate(t *testing.T) {
 			expectedError: errors.New(`invalid name 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'`),
 		},
 		{
-			name: "invalid character name",
+			name: "invalid character name with spaces",
 			inputAction: &Action{
-				Name:    `\//?|?|?%&%@$&£@$)`,
+				Name:    "invalid name with spaces",
 				Command: "env",
 			},
-			expectedError: errors.New(`invalid name '\//?|?|?%&%@$&£@$)'`),
+			expectedError: errors.New(`invalid name 'invalid name with spaces'`),
+		},
+		{
+			name: "invalid character name with nulls",
+			inputAction: &Action{
+				Name:    "invalid\x00name",
+				Command: "env",
+			},
+			expectedError: fmt.Errorf("1 error occurred:\n\t* invalid name 'invalid\x00name'\n\n"), // had to use fmt.Errorf to show the null character
+		},
+		{
+			name: "Emoji characters are valid",
+			inputAction: &Action{
+				Name:    "🇳🇴🇲🇦🇩",
+				Command: "env",
+			},
+			expectedError: nil,
 		},
 		{
 			name: "valid",