go.mod: require a newer version of github.com/google/martian

The only valid semantic-version tags for that module are
three-year-old prereleases (v2.0.0-beta.2), and they predate one of
the packages we need to resolve (github.com/google/martian/httpspec).
Explicitly use a newer pseudoversion.

Change-Id: Ia54e8e9f958e300a61bdf226b8d1e24615b3e453
Reviewed-on: https://go-review.googlesource.com/137316
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/go.mod b/go.mod
index 16fe4ba..7672a0e 100644
--- a/go.mod
+++ b/go.mod
@@ -18,7 +18,7 @@
 	github.com/google/go-cmp v0.2.0
 	github.com/google/go-github v16.0.0+incompatible
 	github.com/google/go-querystring v0.0.0-20170111101155-53e6ce116135 // indirect
-	github.com/google/martian v2.0.0-beta.2+incompatible // indirect
+	github.com/google/martian v2.0.0-beta.2.0.20180813215018-c223d6f7955e+incompatible // indirect
 	github.com/googleapis/gax-go v2.0.0+incompatible // indirect
 	github.com/gopherjs/gopherjs v0.0.0-20180628210949-0892b62f0d9f // indirect
 	github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7
diff --git a/go.sum b/go.sum
index 3afe1f1..900ac75 100644
--- a/go.sum
+++ b/go.sum
@@ -32,8 +32,8 @@
 github.com/google/go-github v16.0.0+incompatible/go.mod h1:zLgOLi98H3fifZn+44m+umXrS52loVEgC2AApnigrVQ=
 github.com/google/go-querystring v0.0.0-20170111101155-53e6ce116135 h1:zLTLjkaOFEFIOxY5BWLFLwh+cL8vOBW4XJ2aqLE/Tf0=
 github.com/google/go-querystring v0.0.0-20170111101155-53e6ce116135/go.mod h1:odCYkC5MyYFN7vkCjXpyrEuKhc/BUO6wN/zVPAxq5ck=
-github.com/google/martian v2.0.0-beta.2+incompatible h1:Sthb/mONxL84r1YMJdDVpZPXwr7GgjxdTYteMGB9tVE=
-github.com/google/martian v2.0.0-beta.2+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
+github.com/google/martian v2.0.0-beta.2.0.20180813215018-c223d6f7955e+incompatible h1:NpYJkB0EcEQF9J8ugxjYyENaRP3ixdr53NJer4p5HIg=
+github.com/google/martian v2.0.0-beta.2.0.20180813215018-c223d6f7955e+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
 github.com/googleapis/gax-go v2.0.0+incompatible h1:j0GKcs05QVmm7yesiZq2+9cxHkNK9YM6zKx4D2qucQU=
 github.com/googleapis/gax-go v2.0.0+incompatible/go.mod h1:SFVmujtThgffbyetf+mdk2eWhX2bMyUtNHzFKcPA9HY=
 github.com/gopherjs/gopherjs v0.0.0-20180628210949-0892b62f0d9f h1:FDM3EtwZLyhW48YRiyqjivNlNZjAObv4xt4NnJaU+NQ=
@@ -61,10 +61,6 @@
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/russross/blackfriday v1.5.1 h1:B8ZN6pD4PVofmlDCDUdELeYrbsVIDM/bpjW3v3zgcRc=
 github.com/russross/blackfriday v1.5.1/go.mod h1:JO/DiYxRf+HjHt06OyowR9PTA263kcR/rfWxYHBV53g=
-github.com/russross/blackfriday v1.5.2-0.20180804101149-46c73eb196ba h1:2VGlXbcObH8g/Nrc76I7/t3Gpj+LZXD5Ot/FM9ZO8r0=
-github.com/russross/blackfriday v1.5.2-0.20180804101149-46c73eb196ba/go.mod h1:JO/DiYxRf+HjHt06OyowR9PTA263kcR/rfWxYHBV53g=
-github.com/russross/blackfriday v2.0.0+incompatible h1:cBXrhZNUf9C+La9/YpS+UHpUT8YD6Td9ZMSU9APFcsk=
-github.com/russross/blackfriday v2.0.0+incompatible/go.mod h1:JO/DiYxRf+HjHt06OyowR9PTA263kcR/rfWxYHBV53g=
 github.com/sergi/go-diff v1.0.0 h1:Kpca3qRNrduNnOQeazBd0ysaKrUJiIuISHxogkT9RPQ=
 github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
 github.com/shurcooL/component v0.0.0-20170202220835-f88ec8f54cc4 h1:Fth6mevc5rX7glNLpbAMJnqKlfIkcTjZCSHEeqvKbcI=
@@ -133,10 +129,6 @@
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180807162357-acbc56fc7007 h1:UnHxDq9ldm4vol94wlSWDF3SU4IyC8IWVWtg266CzoY=
 golang.org/x/sys v0.0.0-20180807162357-acbc56fc7007/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/text v0.0.0-20180807135948-17ff2d5776d2 h1:2+dCqxC9yAjEH1OG0Vzm3MG35jtSXNqMOqA+ZLmJrLQ=
-golang.org/x/text v0.0.0-20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2 h1:z99zHgr7hKfrUcX/KsoJk5FJfjTceCKIp96+biqP4To=
 golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2 h1:+DCIGbF/swA92ohVg0//6X2IVY3KZs6p9mix0ziNYJM=