Mismatch in md5 hash for Eigen dependency in v1.0.0

[alejandrogallo]

When building Eigen in tag v1.0.0, the stored hash for eigen is
apparently wrong and therefore it will not build.
It could be that the eigen people have repackaged
eigen version 3.3.7 and therefore the hash changed.

diff --git a/external/eigen.cmake b/external/eigen.cmake
index 3275d20b..3752f49a 100644
--- a/external/eigen.cmake
+++ b/external/eigen.cmake
@@ -105,7 +105,7 @@ else()
   set(EXTERNAL_SOURCE_DIR   ${PROJECT_BINARY_DIR}/external/source/eigen)
   set(EXTERNAL_BUILD_DIR  ${PROJECT_BINARY_DIR}/external/build/eigen)
   set(EIGEN3_URL https://gitlab.com/libeigen/eigen/-/archive/3.3.7/eigen-3.3.7.tar.bz2)
-  set(EIGEN3_URL_HASH MD5=05b1f7511c93980c385ebe11bd3c93fa)
+  set(EIGEN3_URL_HASH MD5=b9e98a200d2455f06db9c661c5610496)

   message("** Will build Eigen from ${EIGEN3_URL}")