Update ELK images

elasticsearch:
- https://github.com/docker-library/elasticsearch/commit/1c213e9: Remove unused variable
- https://github.com/docker-library/elasticsearch/commit/7b4d714: Update to 7.13.1
- https://github.com/docker-library/elasticsearch/commit/ff453e6: Update to 7.13.0
- https://github.com/docker-library/elasticsearch/commit/a2d24fd: Update to 6.8.16

logstash:
- https://github.com/docker-library/logstash/commit/612616e: Merge pull request https://github.com/docker-library/logstash/pull/102 from infosiftr/arm64
- https://github.com/docker-library/logstash/commit/f7d134e: Add arm64v8 to 7.13.1
- https://github.com/docker-library/logstash/commit/497c199: Update to 7.13.1
- https://github.com/docker-library/logstash/commit/88616b8: Update to 7.13.0
- https://github.com/docker-library/logstash/commit/9f5d90a: Update to 6.8.16

kibana:
- https://github.com/docker-library/kibana/commit/094d900: Add arm64v8
- https://github.com/docker-library/kibana/commit/d8d45c6: Update to 7.13.1
- https://github.com/docker-library/kibana/commit/cc59e7f: Update to 7.13.0
- https://github.com/docker-library/kibana/commit/6b23cd4: Update to 6.8.16

library/elasticsearch

@@ -1,15 +1,15 @@
-# this file is generated via https://github.com/docker-library/elasticsearch/blob/551cff2cb19d99d2c76a8717d7d3007bb23c3a7a/generate-stackbrew-library.sh
+# this file is generated via https://github.com/docker-library/elasticsearch/blob/1c213e964445c73ff44e2ed1ff18e28995800d8e/generate-stackbrew-library.sh
 
 Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/elasticsearch.git
 
-Tags: 7.12.1
+Tags: 7.13.1
 Architectures: amd64, arm64v8
-GitCommit: 67c05f68cd72dd1660feb24692d044747e472666
+GitCommit: 7b4d71467a0b5efee55133fe1b669751de456b45
 Directory: 7
 
-Tags: 6.8.15
+Tags: 6.8.16
 Architectures: amd64
-GitCommit: e1bc20d3147ba582bfaaf3e289ca1070797736f6
+GitCommit: a2d24fd88dbbede4e95e770354a8b0ba614d0502
 Directory: 6

library/kibana

@@ -1,13 +1,15 @@
-# this file is generated via https://github.com/docker-library/kibana/blob/2ec5f3641bcc93b9a8066f19b42630b4e8d570c7/generate-stackbrew-library.sh
+# this file is generated via https://github.com/docker-library/kibana/blob/094d900939e2a66300d48cbf2f3a8e0fc1d51abc/generate-stackbrew-library.sh
 
 Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/kibana.git
 
-Tags: 7.12.1
-GitCommit: 46b36d2319d45441c35e67075106d81856fca123
+Tags: 7.13.1
+Architectures: amd64, arm64v8
+GitCommit: 094d900939e2a66300d48cbf2f3a8e0fc1d51abc
 Directory: 7
 
-Tags: 6.8.15
-GitCommit: d6759ae96883bf483b449f26c97229442e13c5cc
+Tags: 6.8.16
+Architectures: amd64
+GitCommit: 094d900939e2a66300d48cbf2f3a8e0fc1d51abc
 Directory: 6

library/logstash

@@ -1,13 +1,15 @@
-# this file is generated via https://github.com/docker-library/logstash/blob/18d3da965bb702a12edd9d387afd16bd965c5b1c/generate-stackbrew-library.sh
+# this file is generated via https://github.com/docker-library/logstash/blob/f7d134ebe96d21adc7ff6f0bdc46e06db1a642e7/generate-stackbrew-library.sh
 
 Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/logstash.git
 
-Tags: 7.12.1
-GitCommit: d615c7193d244f2274841f73acd0df804b07fd17
+Tags: 7.13.1
+Architectures: amd64, arm64v8
+GitCommit: f7d134ebe96d21adc7ff6f0bdc46e06db1a642e7
 Directory: 7
 
-Tags: 6.8.15
-GitCommit: 3640745741d172b99cb90382e701de77726c43a5
+Tags: 6.8.16
+Architectures: amd64
+GitCommit: f7d134ebe96d21adc7ff6f0bdc46e06db1a642e7
 Directory: 6