Prepare release v1.5.5

Author: tolbrino

CHANGELOG.md

@@ -0,0 +1,10 @@
+# Changelog
+
+## [v1.5.5](https://github.com/Feuerlabs/exometer_core/tree/v1.5.5) (2018-11-01)
+[Full Changelog](https://github.com/Feuerlabs/exometer_core/compare/v1.5.4...v1.5.5)
+
+- Add OTP 21 support and CI coverage [\#114](https://github.com/Feuerlabs/exometer_core/pull/114)
+- Fix handling of cache misses [\#117](https://github.com/Feuerlabs/exometer_core/pull/117)
+- Fix exometer_report documentation [\#81](https://github.com/Feuerlabs/exometer_core/issues/81)
+- Remove default min_heap_size in exometer_probe [\#102](https://github.com/Feuerlabs/exometer_core/pull/102)
+- Switch to rebar3 [\#119](https://github.com/Feuerlabs/exometer_core/pull/119)

src/exometer_core.app.src

@@ -2,7 +2,7 @@
 {application, exometer_core,
  [
   {description, "Code instrumentation and metrics collection package."},
-  {vsn, "1.5.4"},
+  {vsn, "1.5.5"},
   {registered, []},
   {applications,
    [