Add plugin esh.mk to the index/documentation

doc/src/guide/external_plugins_list.asciidoc

@@ -26,6 +26,11 @@ language for the BEAM.
 An https://github.com/inaka/elvis.mk[Elvis plugin] for Erlang.mk.
 Elvis is an https://github.com/inaka/elvis[Erlang style reviewer].
 
+=== esh.mk
+
+An https://github.com/crownedgrouse/esh.mk[Esh template plugin] for Erlang.mk.
+https://github.com/jirutka/esh[Esh] is a simple template engine using shell.
+
 === geas
 
 https://github.com/crownedgrouse/geas[Geas] gives aggregated

index/esh_mk.mk

@@ -0,0 +1,7 @@
+PACKAGES += esh_mk
+pkg_esh_mk_name = esh_mk
+pkg_esh_mk_description = esh template engine plugin for erlang.mk
+pkg_esh_mk_homepage = https://github.com/crownedgrouse/esh.mk
+pkg_esh_mk_fetch = git
+pkg_esh_mk_repo = https://github.com/crownedgrouse/esh.mk.git
+pkg_esh_mk_commit = master

test/Makefile

@@ -165,7 +165,7 @@ $(eval $(foreach t,$(patsubst %.mk,%,$(patsubst plugin_%,%,$(wildcard plugin_*.m
 # Packages.
 
 PACKAGES = $(foreach pkg,$(sort $(wildcard ../index/*.mk)),$(notdir $(basename $(pkg))))
-EXCLUDE_FROM_CHECK = ['ci.erlang.mk', hexer_mk, inaka_mk, 'lfe.mk', rabbitmq_codegen]
+EXCLUDE_FROM_CHECK = ['ci.erlang.mk', esh_mk, hexer_mk, inaka_mk, 'lfe.mk', rabbitmq_codegen]
 
 packages: $(addprefix pkg-,$(PACKAGES))