[ATMOSPHERE-536] [stable/2023.2] ci: update go unit tests (#2074)

This is an automated cherry-pick of #1983
/assign okozachenko1203
diff --git a/roles/defaults/vars.go b/roles/defaults/vars.go
index 4c11748..0799e7d 100644
--- a/roles/defaults/vars.go
+++ b/roles/defaults/vars.go
@@ -3,6 +3,7 @@
 import (
 	"bytes"
 	_ "embed"
+	"strings"
 
 	"github.com/goccy/go-yaml"
 )
@@ -12,14 +13,25 @@
 	varsFile []byte
 )
 
+// Define a global variable for the release value.
+var release = "main"
+
+// Function to replace the {{ release }} placeholders
+func replaceReleaseInYAML(yamlContent []byte, release string) []byte {
+	return []byte(strings.ReplaceAll(string(yamlContent), "{{ atmosphere_release }}", release))
+}
+
 func GetImages() (map[string]string, error) {
+	// Replace {{ release }} with the actual release value
+	modifiedVarsFile := replaceReleaseInYAML(varsFile, release)
+
 	path, err := yaml.PathString("$._atmosphere_images")
 	if err != nil {
 		return nil, err
 	}
 
 	var images map[string]string
-	if err := path.Read(bytes.NewReader(varsFile), &images); err != nil {
+	if err := path.Read(bytes.NewReader(modifiedVarsFile), &images); err != nil {
 		return nil, err
 	}