Merge branch 'gams' into 'master'

GAMS 50.3.0 and updated to yaml

Closes #322

See merge request Pmodules/buildblocks!510

Tools/GAMS/build

@@ -1,7 +1,5 @@
 #!/usr/bin/env modbuild
 
-pbuild::add_to_group 'Tools'
-
 pbuild::prep() {
 	:
 }

Tools/GAMS/files/config.yaml

@@ -0,0 +1,27 @@
+format: 1
+GAMS:
+  defaults:
+    group: Tools
+    relstage: stable
+  shasums:
+  versions:
+    50.3.0:
+      variants:
+        - relstage: stable
+          overlay: merlin
+          use_overlays: [PSI]
+    42.3.0:
+      variants:
+        - relstage: stable
+          overlay: merlin
+          use_overlays: [PSI]
+    31.1.1:
+      variants:
+        - relstage: deprecated
+          overlay: merlin
+          use_overlays: [PSI]
+    30.3.0:
+      variants:
+        - relstage: deprecated 
+          overlay: merlin
+          use_overlays: [PSI]