Fix 404 links to Curry On (#1834)

Author: Philippus

_events/2015-07-06-curryon.md

@@ -6,5 +6,5 @@ location: Prague, Czech Republic
 description: "Academia and industry need to have a talk."
 start: 6 July 2015
 end: 7 July 2015
-link-out: https://www.curry-on.org/2015/
+link-out: https://web.archive.org/web/20250730122351/http://www.curry-on.org/2015/
 ---

_events/2016-07-18-curryon.md

@@ -6,5 +6,5 @@ location: Rome, Italy
 description: "Academia and industry need to have a talk."
 start: 18 July 2016
 end: 19 July 2016
-link-out: https://www.curry-on.org/2016/
+link-out: https://web.archive.org/web/20250730122352/http://www.curry-on.org/2016/
 ---

_events/2017-06-19-curryon.md

@@ -6,5 +6,5 @@ location: Barcelona, Spain
 description: "Academia and industry need to have a talk."
 start: 19 June 2017
 end: 20 June 2017
-link-out: https://www.curry-on.org/2017/
+link-out: https://web.archive.org/web/20240812131857/http://www.curry-on.org/2017/
 ---

_events/2018-07-16-curryon.md

@@ -6,5 +6,5 @@ location: Amsterdam, The Netherlands
 description: "Academia and industry need to have a talk."
 start: 16 July 2018
 end: 17 July 2018
-link-out: https://www.curry-on.org/2018/
+link-out: https://web.archive.org/web/20240225073656/http://www.curry-on.org/2018/
 ---

_events/2019-07-15-curryon.md

@@ -6,5 +6,5 @@ location: London, UK
 description: "Academia and industry need to have a talk."
 start: 15 July 2019
 end: 16 July 2019
-link-out: https://www.curry-on.org/2019/
+link-out: https://web.archive.org/web/20231201170726/https://www.curry-on.org/2019/
 ---