Hey after recent game updates and (still awaiting for 0.4.0 addons update, but pre-release is quite stable) your mod does fail to compile.
here is log from player.log
Compiling addon 'workshop-2603937574'...
Compiling file 'D:\Games\SteamLibrary\steamapps\workshop\content\544550\2603937574\Scripts\HarvesterPatch.cs'...
Compiling file 'D:\Games\SteamLibrary\steamapps\workshop\content\544550\2603937574\Scripts\LetHarvieUseFertilizer.cs'...
Linking addon 'workshop-2603937574'...
[Plugin Compiler - ERROR] 'GameManager' does not contain a definition for 'IsServer'
[Plugin Compiler - ERROR] 'Harvester' does not contain a definition for 'OwnerSteamId' and no accessible extension method 'OwnerSteamId' accepting a first argument of type 'Harvester' could be found (are you missing a using directive or an assembly reference?)
[Plugin Compiler - ERROR] 'DynamicThing' does not contain a definition for 'Prefab' and no accessible extension method 'Prefab' accepting a first argument of type 'DynamicThing' could be found (are you missing a using directive or an assembly reference?)
[Plugin Compiler - ERROR] 'Harvester' does not contain a definition for 'OwnerSteamId' and no accessible extension method 'OwnerSteamId' accepting a first argument of type 'Harvester' could be found (are you missing a using directive or an assembly reference?)
[Plugin Compiler - ERROR] 'Harvester' does not contain a definition for 'OwnerSteamId' and no accessible extension method 'OwnerSteamId' accepting a first argument of type 'Harvester' could be found (are you missing a using directive or an assembly reference?)
[Plugin Compiler - ERROR] 'DynamicThing' does not contain a definition for 'Prefab' and no accessible extension method 'Prefab' accepting a first argument of type 'DynamicThing' could be found (are you missing a using directive or an assembly reference?)
[Plugin Compiler - ERROR] 'Harvester' does not contain a definition for 'OwnerSteamId' and no accessible extension method 'OwnerSteamId' accepting a first argument of type 'Harvester' could be found (are you missing a using directive or an assembly reference?)
[Plugin Compiler - ERROR] 'GameManager' does not contain a definition for 'IsServer'
[Plugin Compiler - ERROR] 'Plant' does not contain a definition for 'NetworkQuantity' and no accessible extension method 'NetworkQuantity' accepting a first argument of type 'Plant' could be found (are you missing a using directive or an assembly reference?)
[Plugin Compiler - ERROR] 'GameManager' does not contain a definition for 'IsServer'
[Plugin Compiler - ERROR] 'Fertiliser' does not contain a definition for 'NetworkQuantity' and no accessible extension method 'NetworkQuantity' accepting a first argument of type 'Fertiliser' could be found (are you missing a using directive or an assembly reference?)
ERROR: Failed to compile addon 'workshop-2603937574'!