Add integration pipeline

Added woodpecker pipeline for linting and unit testing.

.luacheckrc

@@ -0,0 +1,3 @@
+globals = {
+    "vim",
+}

.woodpecker.yml

@@ -0,0 +1,12 @@
+# branches: main
+
+pipeline:
+  code_lint:
+    image: pipelinecomponents/luacheck
+    commands:
+      - luacheck lua/zettelkasten
+
+  unit_tests:
+    image: imega/busted
+    commands:
+      - busted test -C lua

lua/test/files_spec.lua

@@ -91,7 +91,7 @@ describe("get_all_files", function()
                 end,
                 fs_scandir_next = function()
                     if #files == 0 then return nil end
-                    local fname, ftype = table.unpack(table.remove(files))
+                    local fname, ftype = unpack(table.remove(files))
                     return fname, ftype
                 end
             })