ValidationMatchers don't compile on java version 8_60+

[writeoncereadmany]

This is the output of mvn clean test:

[ERROR] /home/dev/projects/validation/src/test/java/co/unruly/util/ValidationMapAndFlatMapTest.java:[15,9] no suitable method found for assertThat(co.unruly.util.Validation<java.lang.Object,java.lang.String>,org.hamcrest.Matcher<capture#1 of ? super co.unruly.util.Validation<? extends java.lang.String,? extends java.lang.Object>>)
method org.junit.Assert.assertThat(java.lang.String,T,org.hamcrest.Matcher<? super T>) is not applicable
(cannot infer type-variable(s) T
(actual and formal argument lists differ in length))
method org.junit.Assert.assertThat(T,org.hamcrest.Matcher<? super T>) is not applicable
(cannot infer type-variable(s) T,U,capture#2 of ? super co.unruly.util.Validation<? extends T,? extends U>,T,U
(argument mismatch; org.hamcrest.Matcher<capture#3 of ? super co.unruly.util.Validation<? extends T,? extends U>> cannot be converted to org.hamcrest.Matcher<? super co.unruly.util.Validation<java.lang.Object,java.lang.String>>))
[ERROR] /home/dev/projects/validation/src/test/java/co/unruly/util/ValidationMapAndFlatMapTest.java:[41,9] no suitable method found for assertThat(co.unruly.util.Validation<java.lang.Object,java.lang.String>,org.hamcrest.Matcher<capture#4 of ? super co.unruly.util.Validation<? extends java.lang.String,? extends java.lang.Object>>)
method org.junit.Assert.assertThat(java.lang.String,T,org.hamcrest.Matcher<? super T>) is not applicable
(cannot infer type-variable(s) T
(actual and formal argument lists differ in length))
method org.junit.Assert.assertThat(T,org.hamcrest.Matcher<? super T>) is not applicable
(cannot infer type-variable(s) T,U,capture#5 of ? super co.unruly.util.Validation<? extends T,? extends U>,T,U
(argument mismatch; org.hamcrest.Matcher<capture#6 of ? super co.unruly.util.Validation<? extends T,? extends U>> cannot be converted to org.hamcrest.Matcher<? super co.unruly.util.Validation<java.lang.Object,java.lang.String>>))
[INFO] 2 errors