In compile command try to release the package manager lock ASAP (#2741)

* In `compile` command try to release the package manager lock ASAP * Applied suggestion from code review

Author: cmaglie

commands/service_compile.go

@@ -22,6 +22,7 @@ import (
 "io"
 "sort"
 "strings"
+"sync"
 "time"
 
 "github.com/arduino/arduino-cli/commands/cmderrors"
@@ -81,6 +82,7 @@ func (s *arduinoCoreServerImpl) Compile(req *rpc.CompileRequest, stream rpc.Ardu
 iferr!=nil {
 returnerr
  }
+release=sync.OnceFunc(release)
 deferrelease()
 
 ifpme.Dirty() {
@@ -358,6 +360,10 @@ func (s *arduinoCoreServerImpl) Compile(req *rpc.CompileRequest, stream rpc.Ardu
 targetBoard.String(), "'build.board'", sketchBuilder.GetBuildProperties().Get("build.board")) +"\n"))
  }
 
+// Release package manager
+release()
+
+// Perform the actual build
 iferr:=sketchBuilder.Build(); err!=nil {
 return&cmderrors.CompileFailedError{Message: err.Error()}
  }