Tune default GOGC

Adjust the default GOGC value to 75. This is less of a memory savings,
but has less impact on CPU use.

Signed-off-by: SuperQ <superq@gmail.com>

config/config.go

@@ -154,7 +154,7 @@ var (
 
 	DefaultRuntimeConfig = RuntimeConfig{
 		// Go runtime tuning.
-		GoGC: 50,
+		GoGC: 75,
 	}
 
 	// DefaultScrapeConfig is the default scrape configuration.

docs/configuration/configuration.md

@@ -125,7 +125,7 @@ runtime:
   # Configure the Go garbage collector GOGC parameter
   # See: https://tip.golang.org/doc/gc-guide#GOGC
   # Lowering this number increases CPU usage.
-  [ gogc: <int> | default = 50 ]
+  [ gogc: <int> | default = 75 ]
 
 # Rule files specifies a list of globs. Rules and alerts are read from
 # all matching files.