updating podspec

Author: amratab

.swift-version

@@ -8,7 +8,7 @@ Pod::Spec.new do |s|
   s.requires_arc = true
 
   # 2
-  s.version = "0.7.1"
+  s.version = "0.7.2"
 
   # 3
   s.license = { :type => "MIT", :file => "LICENSE" }
@@ -36,5 +36,6 @@ Pod::Spec.new do |s|
   s.framework = "UIKit"
 
   s.source_files = "FlexibleSteppedProgressBar/**/*.{swift}"
+  s.swift_version = '5.1'
 
 end