Fix deprecation warnings

Author: j8r

spec/cpu_spec.cr

@@ -5,7 +5,7 @@ def assert_cpu_load(&)
   # Wait enough time to have measurable load
   cpu_usage = 0
   9.times do
-    sleep 1
+    sleep 1.seconds
     cpu_usage = yield
 
     break if 0 < cpu_usage <= 100

spec/pid/stat_spec.cr

@@ -20,7 +20,7 @@ describe Hardware::PID::Stat do
     Hardware::PID.each do |pid|
       spawn do
         stat = pid.stat
-        sleep 4
+        sleep 4.seconds
         channel.send stat.cpu_usage!
       rescue ex : Hardware::Error
         channel.send 0

src/pid.cr

@@ -62,7 +62,7 @@ struct Hardware::PID
 
   # Returns `/proc/``#pid``/exe` if readable.
   def exe : String
-    File.real_path "/proc/#{@number}/exe"
+    File.realpath "/proc/#{@number}/exe"
   end
 
   def exists? : Bool