allow task to get protoc bin name from env

Author: masci

Diff for: Taskfile.yml

@@ -4,7 +4,7 @@ tasks:
   protoc:
     desc: Compile protobuf definitions
     cmds:
-      - protoc --proto_path=rpc --go_out=plugins=grpc,paths=source_relative:rpc ./rpc/commands/*.proto
+      - '{{ default "protoc" .PROTOC_BINARY }} --proto_path=rpc --go_out=plugins=grpc,paths=source_relative:rpc ./rpc/commands/*.proto'
 
   build:
     desc: Build the project

Diff for: appveyor.yml

@@ -10,6 +10,7 @@ skip_branch_with_pr: true
 environment:
   GOPATH: c:\gopath
   PROTOC_PATH: c:\protoc
+  PROTOC_BINARY: protoc.exe
   # add protoc, gopath and override default Python 2.7
   PATH: $(PROTOC_PATH)\bin;$(GOPATH)\bin;C:\Python37;C:\Python37\Scripts;$(PATH)