upgrade opam file to opam 2

Makefile

@@ -29,14 +29,8 @@ build-dep: build-dep/opam phony
 	@# that are incompatible with our build requirements.
 	@# To achieve this, we create a fake opam package that has our build-dependencies as
 	@# dependencies, but does not actually install anything itself.
-	@echo "# Pinning build-dep package." && \
-	  if opam --version | grep "^1\." -q; then \
-	    BUILD_DEP_PACKAGE="$$(egrep "^name:" build-dep/opam | sed 's/^name: *"\(.*\)" */\1/')" && \
-	    opam pin add -k path $(OPAMFLAGS) "$$BUILD_DEP_PACKAGE".dev build-dep && \
-	    opam reinstall $(OPAMFLAGS) "$$BUILD_DEP_PACKAGE"; \
-	  else \
-	    opam install $(OPAMFLAGS) build-dep/; \
-	  fi
+	@echo "# Installing build-dep package."
+	@opam install $(OPAMFLAGS) build-dep/
 
 # Some files that do *not* need to be forwarded to Makefile.coq
 Makefile: ;

descr

-This is the Coq development of the Iris Project.

opam

-opam-version: "1.2"
+opam-version: "2.0"
 name: "coq-iris"
-synopsis: "This is the Coq development of the Iris Project"
 maintainer: "Ralf Jung <jung@mpi-sws.org>"
 authors: "The Iris Team"
 homepage: "http://iris-project.org/"
 bug-reports: "https://gitlab.mpi-sws.org/iris/iris/issues"
+dev-repo: "git+https://gitlab.mpi-sws.org/iris/iris.git"
 license: "BSD"
-dev-repo: "https://gitlab.mpi-sws.org/iris/iris.git"
-build: [make "-j%{jobs}%"]
-install: [make "install"]
-remove: ["rm" "-rf" "%{lib}%/coq/user-contrib/iris"]
+synopsis: "This is the Coq development of the Iris Project"
+
 depends: [
+  "ocaml"
   "coq" { (= "8.8.2") | (>= "8.9.1" & < "8.12~") | (= "dev") }
   "coq-stdpp" { (= "dev.2019-11-22.2.16eb222f") | (= "dev") }
 ]
+
+build: [make "-j%{jobs}%"]
+install: [make "install"]