[ci] Use updated feflow 8.1 from !140.

Related #53 (closed), !150 (merged), https://github.com/red5alex/ifm_contrib/pull/13.

.devcontainer/Dockerfile

@@ -5,8 +5,13 @@ ENV \
     # Adapt when changing base image:
     DIST_DIR=ub2204x64
 RUN apt-get update \
-    && apt-get install -yq --no-install-recommends gpg curl ca-certificates \
-    && curl -fsSL https://download.feflow.com/download/FEFLOW/linux/dhi-feflow-key.asc | gpg --dearmor | sudo tee /usr/share/keyrings/feflow.gpg > /dev/null \
+    && apt-get install -yq --no-install-recommends gpg curl ca-certificates
+# Error: The following packages have unmet dependencies:
+#   feflow-console81 : Depends: aspnetcore-runtime-6.0 but it is not installable
+# Add dot net repos for debian 12 (bookworm base image)
+RUN curl -fsSL https://packages.microsoft.com/config/debian/12/packages-microsoft-prod.deb -o packages-microsoft-prod.deb \
+    && dpkg -i packages-microsoft-prod.deb && rm packages-microsoft-prod.deb
+RUN curl -fsSL https://download.feflow.com/download/FEFLOW/linux/dhi-feflow-key.asc | gpg --dearmor | sudo tee /usr/share/keyrings/feflow.gpg > /dev/null \
     && echo "deb [arch=amd64 signed-by=/usr/share/keyrings/feflow.gpg] https://download.feflow.com/download/FEFLOW/linux/apt-repo/$DIST_DIR stable main" | sudo tee /etc/apt/sources.list.d/feflow.stable.list \
     && apt-get update \
     && apt list | grep feflow  \