Add trailing slash if it doesn't exist (#228)

Co-authored-by: Tim Jacomb <[email protected]>

Author: bsloan-icl

src/main/java/org/jenkinsci/plugins/azurekeyvaultplugin/AzureCredentialsProvider.java

@@ -140,6 +140,12 @@ private static Collection<IdCredentials> fetchCredentials() {
             if (StringUtils.isEmpty(keyVaultURL) || StringUtils.isEmpty(credentialID)) {
                 return Collections.emptyList();
             }
+
+            // If keyVaultURL does not have a trailing slash, add one
+            if (!keyVaultURL.endsWith("/")) {
+                keyVaultURL += "/";
+            }
+
             SecretClient client = SecretClientCache.get(credentialID, keyVaultURL);
 
             String labelSelector = extractLabelSelector();