[GR-10199] Add CHANGELOG file.

PullRequest: fastr/1583

CHANGELOG.md

+
+# 1.0 RC 3
+
+Added missing R builtins and C API
+
+* vmmin
+* SETLENGTH, TRUELENGHT, SET_TRUELENGTH
+* simplified version of LEVELS
+* addInputHandler, removeInputHandler
+
+Bug fixes
+
+* The plotting window did not display anything after it was closed and reopened.
+* Various smaller issues discovered during testing of CRAN packages.
+
+New features
+
+* Script that configures FastR for the current system (jre/languages/R/bin/configure_fastr) does not require Autotools anymore.
+* Users can build a native image of the FastR runtime. The native image provides faster startup and slightly slower peak performance. Run jre/languages/R/bin/install_r_native_image to build the image.