[skip ci] readme: fixing anchor links

Author: mwarusz

README.md

@@ -137,5 +137,5 @@ docker run -it --rm igfuw/libmpdataxx:latest
 ```
 This will open an interactive `bash` in the container
 and your working directory will be `/usr/local/src/libmpdataxx`.
-You can repeat the [step 2](#2.-to-perform-unit-tests:)
-and the [step 3](#3.-to-reproduce-all-results-from-the-gmd-paper:) from the previous part to run the tests.
+You can repeat the [step 2](#2-to-perform-unit-tests)
+and the [step 3](#3-to-reproduce-all-results-from-the-gmd-paper) from the previous part to run the tests.