Bumping to fsharp 4.1.18 (#2920)

* Bumping to fsharp 4.1.18

Updating mono based image with 4.1.18
Update to maintainers

* Multiple maintainers - adding comma

* Using latest commit hash with correct maintainers

library/fsharp

@@ -1,14 +1,19 @@
-Maintainers: Henrik Feldt <[email protected]> (@haf)
+Maintainers: Dave Curylo <[email protected]> (@ninjarobot),
+             Steve Desmond <[email protected]> (@stevedesmond-ca)
 GitRepo: https://github.com/fsprojects/docker-fsharp.git
 
-Tags: latest, 4, 4.1, 4.1.0.1
-GitCommit: 289a5e0066c69255c055dd5ee22f2e583d37fab4
-Directory: 4.1.0.1
+Tags: latest, 4, 4.1, 4.1.18
+GitCommit: a28196740e38035beea04c41d5862136413281e3
+Directory: 4.1.18/mono
+
+Tags: 4.1.0.1
+GitCommit: a28196740e38035beea04c41d5862136413281e3
+Directory: 4.1.0.1/mono
 
 Tags: 4.0, 4.0.1, 4.0.1.1
-GitCommit: 289a5e0066c69255c055dd5ee22f2e583d37fab4
+GitCommit: a28196740e38035beea04c41d5862136413281e3
 Directory: 4.0.1.1
 
 Tags: 4.0.0.4
-GitCommit: 289a5e0066c69255c055dd5ee22f2e583d37fab4
+GitCommit: a28196740e38035beea04c41d5862136413281e3
 Directory: 4.0.0.4