yaml 0.8.32 broke tests

[felixonmars]

Updating to yaml 0.8.32 seems to break the test suite of pandoc-citeproc with errors like:

--- expected    2018-07-10 16:35:57.989475894 +0800
+++ actual      2018-07-10 16:35:57.989475894 +0800
@@ -15,3 +15,3 @@
   publisher-place: Location
-  page: '100-200'
+  page: 100-200
   volume: '3'
@@ -33,3 +33,3 @@
   publisher-place: Location
-  page: '100-200'
+  page: 100-200
   volume: '3'
[biblio2yaml/maron.biblatex] PASSED
[biblio2yaml/basic.bibtex] FAILED
--- expected    2018-07-10 16:35:58.222809766 +0800
+++ actual      2018-07-10 16:35:58.222809766 +0800
@@ -22,3 +22,3 @@
   container-title: Journal of Generic Studies
-  page: '33-34'
+  page: 33-34
   volume: '6'
119 passed; 44 failed; 0 skipped; 0 errored.

I assume it can be safely skipped, though.

[jgm]

Fixed now; we just require yaml >= 0.8.32 and updated the test suite.