Add DTx function, check and testHEADmain

The tolerance of one test had to be increased in test_deSolve.R,
and four vdiffr snapshots with negligible differences were updated.

Tests run with a maximum of 16 cores when running in the Agroscope
Apptainer environment.

1 files changed, 7 insertions, 1 deletions

diff --git a/NEWS.md b/NEWS.md
index 82f6aa4d..bbdc1b29 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,4 +1,10 @@
-# mkin 1.2.10 (unreleased)
+# mkin 1.2.11 (unreleased)
+
+## New features
+
+- 'R/endpoints.R': Introduce the function `DTx` that makes it easy to calculate various types of DTx values such as DT50, DT90 and pseudo-half-lives calculated from DT90 or from the slow phase of biphasic models.
+
+# mkin 1.2.10 (2025-05-13)
 
 ## New features