audit log query options should use url tag

[sfunkhouser]

When using the query option params for the audit log I noticed the filters were not working, for example, when setting:

searchPhrase := "actor:sfunkhouser"
include := "all"

opts := &github.GetAuditLogOptions{
		Phrase:  &searchPhrase,
		Include: &include,
	}

The results returned contained other activites besides the listed actor. Upon further investigation, I noticed the query string being sent was:

Include=all&Phrase=actor%3Asfunkhouser

Although, I don't understand why these are case sensitive, when testing with

include=all&phrase=actor%3Asfunkhouser

The expected results are returned.

Looking at the other ...Options structs in this repo I saw that those all use the url tag instead of json. Switching to this allowed for the correct string to be used in the the query string and resulting data back was correct.

[codecov]

Codecov Report

Merging #2128 (4120f43) into master (72ec8bb) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2128   +/-   ##
=======================================
  Coverage   97.78%   97.78%           
=======================================
  Files         112      112           
  Lines        9970     9970           
=======================================
  Hits         9749     9749           
  Misses        154      154           
  Partials       67       67           

Impacted Files	Coverage Δ
github/orgs_audit_log.go	100.00% <ø> (ø)

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[gmlewis]

Thank you, @sfunkhouser !
LGTM.
Merging.