persistent_tasks: suppress logs from Pkg.jl

By using `io=devnull` option, which is only available in Julia 1.9
and above.

src/persistent_tasks.jl

@@ -131,9 +131,15 @@ function precompile_wrapper(project, tmax)
             return false
         end
         wrapperdir = tempname()
-        wrappername, _ = only(Pkg.generate(wrapperdir))
-        Pkg.activate(wrapperdir)
-        Pkg.develop(PackageSpec(path = pkgdir))
+        @static if VERSION ≥ v"1.9"
+            wrappername, _ = only(Pkg.generate(wrapperdir; io = devnull))
+            Pkg.activate(wrapperdir; io = devnull)
+            Pkg.develop(PackageSpec(path = pkgdir); io = devnull)
+        else
+            wrappername, _ = only(Pkg.generate(wrapperdir))
+            Pkg.activate(wrapperdir)
+            Pkg.develop(PackageSpec(path = pkgdir))
+        end
         statusfile = joinpath(wrapperdir, "done.log")
         open(joinpath(wrapperdir, "src", wrappername * ".jl"), "w") do io
             println(
@@ -151,7 +157,11 @@ end
             )
         end
         # Precompile the wrapper package
-        cmd = `$(Base.julia_cmd()) --project=$wrapperdir -e 'push!(LOAD_PATH, "@stdlib"); using Pkg; Pkg.precompile()'`
+        @static if VERSION ≥ v"1.9"
+            cmd = `$(Base.julia_cmd()) --project=$wrapperdir -e 'push!(LOAD_PATH, "@stdlib"); using Pkg; Pkg.precompile(; io = devnull)'`
+        else
+            cmd = `$(Base.julia_cmd()) --project=$wrapperdir -e 'push!(LOAD_PATH, "@stdlib"); using Pkg; Pkg.precompile()'`
+        end
         proc = run(cmd, stdin, stdout, stderr; wait = false)
         while !isfile(statusfile) && process_running(proc)
             sleep(0.5)
@@ -172,6 +182,10 @@ end
         return success
     finally
         isdefined(Pkg, :respect_sysimage_versions) && Pkg.respect_sysimage_versions(true)
-        Pkg.activate(prev_project)
+        @static if VERSION ≥ v"1.9"
+            Pkg.activate(prev_project; io = devnull)
+        else
+            Pkg.activate(prev_project)
+        end
     end
 end