Replace hard-coded version number with http_version variable (#47)

* replace hard-coded version number with http_version variable

* Storing package version to http_version.90

Author: rajkumardongre

src/http/http_client.f90

@@ -26,6 +26,7 @@ module http_client
     use http_request, only: request_type
     use http_response, only: response_type
     use http_pair, only: append_pair, pair_has_name, pair_type
+    use http_version, only: VERSION_STRING
 
     implicit none
 
@@ -94,10 +95,10 @@ function new_request(url, method, header, data, form, file, timeout, auth) resul
             request%header = header
             ! Set default request headers.
             if (.not. pair_has_name(header, 'user-agent')) then
-              call append_pair(request%header, 'user-agent', 'fortran-http/0.1.0')
+              call append_pair(request%header, 'user-agent', 'http-client/'//VERSION_STRING)
             end if
         else
-            request%header = [pair_type('user-agent', 'fortran-http/0.1.0')]
+            request%header = [pair_type('user-agent', 'http-client/'//VERSION_STRING)]
         end if
 
         ! setting the request data to be send

src/http/http_version.f90

@@ -0,0 +1,9 @@
+module http_version
+    !! This module store information regarding version
+    !! number of package
+    integer, parameter, public :: VERSION_MAJOR = 0
+        !! major version number
+    integer, parameter, public :: VERSION_MINOR = 1
+        !! minor version number
+    character(len=*), parameter, public :: VERSION_STRING = achar(VERSION_MAJOR + 48) // '.' // achar(VERSION_MINOR + 48)
+end module http_version